PDA

View Full Version : Keen eyes welcome: gas tank question



Ghost
01-07-2009, 01:04 PM
I have mentioned before that my Nova has two 5.7s and only one fuel pickup. Rather than rename it "Starvin Marvin", I need another pickup. And I REALLY don't want to have to pull the tank.

The boat's up for the winter and thus I can't look at it now. And I was too busy with other projects even to remove the cover and peek at it. But I do have a grainy old Zapruder-Film picture from the restoration, when the tank was installed.

I'm curious if all you experienced folks can make out whether I have a nice removable panel on top of the tank? Something that would enable me to pull a small panel, leaving the tank intact, and install a second sender, and then replace the panel. And without 100% draining and cleaning out the tank. Right above the yellow and white stickers, in the center, is where the existing sending unit is installed. Looks like there might be a cleanout panel there, no?

Here's the picture. All thoughts welcome. (Don, you might need to scrap the i-Phone for this one too.)

Regards,

Mike

MOP
01-09-2009, 03:58 PM
Can you post a picture of just the area by where all the plumbing is, I have seen a pickup added but need a better view. P.S. PM me remind me to check back.

Phil

Ghost
01-10-2009, 11:53 AM
Thanks--sadly, this is the best shot I have until April, when I can get the boat back down from the rack again. So for now, it's all about the educated guess... :)

Ghost
07-05-2009, 10:02 AM
Just following up after all these months.

Good news is that I do have a removable panel, as the picture shows. So there should be some reasonable way to add another fuel pickup for a fully independent second fuel line. (It's pretty crowded on the current panel, so maybe I need to have another panel made I suppose.)

But if West has the parts, I have a hope today of rigging a portable tank and seeing if that second 3/8" fuel line (rather than one line that splits to feed both engines) bumps my max RPM and speed way up. <crossing fingers> If not today, then pretty soon I think.

Ghost
07-06-2009, 11:22 AM
Easy enough to reconfigure the panel. While I was in there I'd make em both 1/2" pickups. you know, "just in case" :D :D :D

LOL, and hey, is there any such animal as 1/2" fuel line and parts? I assumed there must be and still believe it has to exist, but I did a bunch of Google searches (lots of ways) and didn't find any, which shocked me. Guys running monster stuff from 500-1200HP have to use something, but maybe I'm just looking in the wrong places. Is this stuff you only find in the racing world?

The fuel pickup in my tank may well be 1/2 or more already (the barb attached to the elbow where the pickup comes out of the panel is bigger than than barbs for 3/8" fuel hose--but I forgot to measure it exactly yesterday--doh!). Suggesting *maybe* with the right hose on it and the right splitter, I might not need to make any mods below the cleanout panel and can keep the tank sealed up.

SAD thing is my trip yesterday was a disappointment. I cut out several segments of my fuel lines to rig a small portable tank with a 3/8" line of its own. Saw a clear 100RPM jump out of both engines (solidly at 3600RPM or a hair more) and a shade more than 1 extra knot, GPS. Definite improvement, but I was hoping for a lot more (like, what you would get with the engines up toward 5000 RPM). I also tried propping open the motorbox a bit just in case I've been starved for air as well as fuel, but that changed nothing.

So, I'm scratching my head. Sounds like I DID have a bit of a fuel supply issue, given a clear but modest improvement using two lines, but clearly there are still other limiting factors. So, if I want to go forward toward what should be a 48-50 MPH boat, I should do a permanent upgrade of the fuel lines, and keep hunting for whatever else is holding me back. (carb secondaries, compression, propping, whatever) This logic sound right?

Along those lines, if the fuel pickup is half inch already (which the big barb suggests it might be) I suspect I could likely do the fuel system upgrade entirely above the panel, meaning without opening up the tank at all, if I could find a few more parts to remove one 15 inch long bottleneck of 3/8" hose that splits into two 3/8" hoses. Any suggestions on where to get 1/2" fuel line components are most welcome. I'd love to save the time, money, and hassle of removing the existing cleanout panel and having something new fabricated.

By my math, (assuming fuel flow is proportional to the cross-sectional area of the fuel line, and splits don't matter too much, just the size of the pipes being large enough all the way through), a half inch line properly split into two 3/8 inch lines should be fine, or pretty close to fine. (.53" inside diameter would be about double the area of a 3/8" line, so a single 1/2" line would be about 89% of the cross-sectional aread of two 3/8" lines, *pretty close*.) If anyone knows better, I'd appreciate the benefit of your experience.

Thanks,

Mike

To facilitate any answers or advice people may have, here were my questions again:
1. Is there any such animal as 1/2" fuel line and parts?
2. If so, anyone know where I can find the stuff?
3. Given yesterday's test, upgrading the fuel system obviously seems like a necessary part of what I need to do, but please yell if anyone thinks otherwise.
4. The math above suggests to me I might be able to upgrade a little bit of my fuel system to 1/2" (if it exists) rather than having any new pickups put into the tank. Thoughts/suggestions/experience on this?

MOP
07-06-2009, 04:55 PM
IMO 1/2" on a 350 is over kill, it just can't suck enough to warrant the swap. I run 3/8 on my 383 and have before correct propping turned 5,600 few times now setup for 5,000. My setup also has dual spin on fuel filters in series and never starves.

Phil

MOP
07-06-2009, 07:31 PM
MOP, you need to learn to read the whole thread sometimes ;) :D :kingme:

Misunderstood, I was on the two 3/8"'s plan, a single 1/2" will flow a little short of two 3/8's but should more then cover it.

Ghost
07-06-2009, 09:30 PM
Thanks guys. I have not tried inline electric pumps.

Just a progress update--I did find some 1/2" feed hose today. And a few parts to fit, not a lot yet, but some. (Also talked to the company that custom built the tank. They sounded very willing to talk options, and said they'd pull the original drawings and give me a call. So I think one way or another we can cover getting some plumbing right, and then it's on to other aspects of the system, as Poodle was talking about.

One general question (which I will also pose to the tank builder): what is std practice to avoid dissimilar metal issues with fuel tanks? Do people try to use aluminum parts on anything directly connected to the tank? Seems like a good idea. I notice I see a few aluminum hose barb fittings mixed in with all the brass ones (have NOT found a half inch aluminum one yet) as one example, and thought galvanism might be why. Also, looking at the parts (again, see picture above for reference), at least SOME of what I'm looking at just can't be aluminum, right? (The filler hose connection for one doesn't look like aluminum to me.)

Do people have some fancy isolation materials to keep the metals from eating each other? I would think this would be pretty settled territory, but the tinkertoys at West Marine and other places have me scratching my head on the best (or even standard) practice.

Appreciate the thoughts and advice,

Mike

Ghost
07-06-2009, 09:49 PM
I'll bet they can build (or modify the existing) you a dual pickup plate no problem.. Twin 3/8 lines are fine IMO, but if your worried about the future they can put the 1/2" pickups in now and you can use a 1/2 male by 3/8 female ell on each one..

This sounds like a really good bit of forward thinking, thanks. Really no reason not to if they fabricate a new panel. Just options.

(As an aside, I also wonder about the placement of the pickup. It's pretty far forward. I figure there'd be a lot of fuel still in the tank when it would run dry at a normal running angle. Maybe that serves as an effective reserve, where flattening out off plane would let me at the last 10 or 15 gallons for creeping along. But switching to pickups further aft would probably be nicer, though not needed and would also require cutting into the tank. Not even sure how anyone does that safely without pulling it and scrubbing it out with dish soap or something to avoid an explosion.)

Ghost
07-07-2009, 10:48 AM
Hook up a hose from the tank to the exhaust pipe of a running vehicle and weld it whilst it is running..

Could the tank be flipped around?

Funny, my only half-ass thought about doing it in situ was using dry ice to purge the oxygen, but exhaust sounds much simpler and more robust for ensuring plenty of supply.

Very good thought on spinning it around. It looks pretty symmetric for fit (the builder can tell me, but I'd need to extend the filler and vent lines, and probably (unless the holes are perfectly symmetric, fabricate a new plate anyhow, since the big filler and such would be in the way if it didn't stay at the forward end of the panel. And I'd also probably have to rework how the feed lines run. And I'm also not sure I don't lose overhead clearance the further I move aft...gotta look at that. The filler hose would be the issue for that more than anything, due to size.

I'm curious now about whether a simple second panel (two pickups and that's it) could be prefabbed for installation further aft. I could easily reconfigure the feed lines to run off of that.

I could even put a valve or two in to perpetuate a reserve system based on run angle if I got nutty. (Run normally on one pickup from the the forward panel and one from the aft panel.) If an engine conks due to sucking air up front, flip the selector to run both from the aft pickups. That may be crazy Rube-Goldberging I suppose--just kinda thinking out loud.

But we do have an aluminum welder/fabricator at the yard where I keep the boat. Could probably block it up and do the car exhaust trick, and and cut an access hole in the the aft end and drop in a prefabbed panel with two pickups in it.

That'll dump aluminum shards into the tank though--one would hope the separator/filter would take care of that but I hate the thought of the stuff going through to the motors. Not like I can even expect fishing with a magnet on a string would get anything out. Think the Racors with their 2-10 micron filters are enough, or are the shavings not safe to drop into the tank at all?

I suppose they might also be able to weld a panel flat on top without cutting a hole first, for more structure, and then drill holes for pickups with a vacuum, to minimize the shavings that fell in, and then tap them, and drop the pickups in that way. Or something. Hmmmm...

Ghost
07-07-2009, 12:24 PM
No doubt--thanks for all the advice. I'll find something that covers this. The hard part is downstream anyhow, figuring out what else is wrong and fixing that.

Ghost
07-19-2009, 11:53 PM
Couple things.

I just replaced a bunch of my fuel system. Didn't get the engines up to speed by any stretch, but should eliminate some things. And, if a compound problem, should have gotten rid of some parts of it.

First, some lessons learned.

Talked to the custom tank builder. Their word: use aluminum fittings when connecting directly to an aluminum tank. All of mine are aluminum EXCEPT the sending unit for the gauge, which is part stainless because that's all that's made.


Talked to Racor. Their words:

The actual paper filters are the same, gas or diesel, just a granularity spec (microns). For gas, they say you should have little need to worry about filtering below 10 microns. Diesel often has two stages, with both a coarse and a fine filter.
For a 310 HP engine such as mine, use at least a 45 gph rated filter.
The filter unit head is anodized aluminum. Best fittings to use are stainless steel. Brass is good, not best. (The units appear to ship with some sort of steel plugs, but I cannot tell what sort. Stupid me forgot to ask about using aluminum, which is harder to find but seems like it would be as good as anything for galvanic purposes, even if less appealing for other reasons.)
A 2 micron filter and a 10 micron filter, each rated for x GPH, will pass x GPH when new, with gas OR diesel. The 2 micron will just clog sooner and reduce flow. (Not sure I fully believe the first part where gas and diesel will both flow through at x GPH, as they have different densities/viscosities, but that's just my opinion.)
My observations include:

It is interesting to me that the typical rule of thumb is use at least a 3/8" fuel line for a 350, but the Racor filters don't get up to 3/8" ins and outs until you get all the way up to a filter rated for 90 GPH. (Even though they told me to use at least a 45GPH filter per 350.)
McMaster-Carr has a great website, great service, and a great selection of fittings. I was able to get all sorts of goodies to rebuild my fuel lines. Some aluminum, some brass, and some stainless seemed optimum, and they had it all and much much more.
I found a pipe dope called Gasoila, which claims to be good for many metals and for all sorts of fuels, from diesel to gas to 85% ethanol blends.
I ran into some sources that said "don't use teflon tape in fuel systems, and don't count on it sealing." Dunno if true, but my pipe dope feels like it should do the job well.
Now, back to my boat and her under-achievement.

This weekend, I removed my 30GPH Racor "diesel" 2 micron filters and put in a pair of 90GPH Racor 10 micron "gas" filters. And I got rid of the single 3/8 inch line from the tank pickup and the 3/8" T that splits to go to each motor. My fuel pickup in the tank is half inch, and now all the plumbing from it is also half inch until AFTER it splits, where it then drops to 3/8ths per line. Then each 3/8" line goes through the 90GPH rated Racors. Should not be too limiting I don't think.

But no improvement in performance. Still stuck with about 3600 RPM per motor and 44mph. Thinking I should be able to get up near 5000 RPM and 50 MPH. The thing that is odd to me is that both motors seem identical, so I have trouble thinking there is a sickness as opposed to a matching design or configuration problem. Why would compression, or something else, be SO evenly sick in both motors, when they are only a couple years old?

But more odd, if I did the math right, something doesn't add up at all.

Can V-drives be installed backwards? Seems crazy, but when I run the numbers based on my RPM, my GPS speed, my v-drive gear spec, and my thoroughly tested props (with fancy computer testing printouts), my spreadsheet of RPM and speed is curious. In short, IF the prop specs are correct, and the RPM are correct, and the GPS speed is correct, and my 1:15 to 1 v-drives are correct, then my actual GPS speed IS EXCEEDING my theoretical speed based on prop pitch. Put another way, my prop slip is NEGATIVE. This CANNOT be.

As I'm trying to imagine a simple explanation (when I have a lot of confidence in the GPS speed, the tachs, and the prop specs), if I switch the numbers out like they rebuilt the boat with the v-drive gear ratio reversed, the prop slip numbers look pretty right to me for an inboard. (25% slip down at 2000 RPM, dropping off to around 18% for a while, then climbing up to about 25% again at 3600, with the boat within about 6mph of what it should do.) Maybe those slip numbers are not appropriate, I'm taking a SWAG, but they SURELY make a lot more sense than negative slip. :)

Anyhow, is accidentally reversing v-drives even possible, with the physical connections on them? Seems like it's somewhere between unlikely and just-plum-crazy to me. I'll probably go look at the boat tomorrow, but I thought of this after hours today and it is up on the storage rack right now.

But what has me thinking this is twofold. If the engines are sick, they sound awfully good and are curiously evenly sick. But even more important, if the gearing and GPS and tachs and computer-tested prop specs are all right, how on Earth could I be going FASTER than the theoretical prop maximum speed? That just ain't happening.

Thanks for any thoughts,

Mike

Conquistador_del_mar
07-20-2009, 01:14 AM
Anyhow, is accidentally reversing v-drives even possible, with the physical connections on them? Seems like it's somewhere between unlikely and just-plum-crazy to me. I'll probably go look at the boat tomorrow, but I thought of this after hours today and it is up on the storage rack right now.

Thanks for any thoughts,

Mike

Mike,
It seems to me that you would be smart to first make sure of the V drive ratios. A relatively easy thing to do would be to disconnect at the tranny and mark both the output to the V drive and the drive shaft out of it. You will then be able to make sure of the ratio by counting the revolutions as you turn it by hand. Aren't most V drives underdrives? Been too long since I had one in an old Corsican - lol. Bill

Ghost
07-20-2009, 01:35 AM
Mike,
It seems to me that you would be smart to first make sure of the V drive ratios. A relatively easy thing to do would be to disconnect at the tranny and mark both the output to the V drive and the drive shaft out of it. You will then be able to make sure of the ratio by counting the revolutions as you turn it by hand. Aren't most V drives underdrives? Been too long since I had one in an old Corsican - lol. Bill

Bill,

Thanks, and that's what I'm hoping to do tomorrow--check the ratio. Not sure how much I need to take apart to do it (never taken any of a drivetrain apart) but I was thinking maybe I could disconnect at the u-joint. Or, find some nice handy markings. And was also thinking about whether there is any clever way to measure it without disconnecting but so far I got nothin simple, and all ideas would require getting blocked up so I wasn't trying to do it underway. Some sort of disconnect and turning it all by hand seems like the surest road right now.

And yes, all the ones I recall seeing written about said they were underdrives.

I'm just trying to figure if I'm nuts or not. On the one hand, I have trouble imagining anyone installing them backwards. On the other, it feels like a lot of the numbers are pointing that way and it would explain a lot.

IF they are backwards, I'm REALLY hopin' they are not too hard to flip. (Angle between the shafts should be the same, but unless the stringer mounts are symmetric AND the plane between the two shafts is parallel to the stringer planes where the drive mounts, I could see it being a huge mess.)

Mike

Conquistador_del_mar
07-20-2009, 11:10 AM
Bill,

Thanks, and that's what I'm hoping to do tomorrow--check the ratio. Not sure how much I need to take apart to do it (never taken any of a drivetrain apart) but I was thinking maybe I could disconnect at the u-joint. Or, find some nice handy markings. And was also thinking about whether there is any clever way to measure it without disconnecting but so far I got nothin simple, and all ideas would require getting blocked up so I wasn't trying to do it underway. Some sort of disconnect and turning it all by hand seems like the surest road right now.

And yes, all the ones I recall seeing written about said they were underdrives.

I'm just trying to figure if I'm nuts or not. On the one hand, I have trouble imagining anyone installing them backwards. On the other, it feels like a lot of the numbers are pointing that way and it would explain a lot.

IF they are backwards, I'm REALLY hopin' they are not too hard to flip. (Angle between the shafts should be the same, but unless the stringer mounts are symmetric AND the plane between the two shafts is parallel to the stringer planes where the drive mounts, I could see it being a huge mess.)

Mike

Mike,
It dawned on me that you might not have 1:1 ratio trannies. Bill

Ghost
07-20-2009, 11:15 AM
Mike,
It dawned on me that you might not have 1:1 ratio trannies. Bill

I've looked at those before, and am almost positive they're stamped 1:1 on the housings, but will double-check that too, thanks. I very much appreciate the thoughts. -Mike

Ghost
07-20-2009, 11:58 AM
Run the numbers using a 1.21 ratio..




They get even more ridiculous if I assume a 1.21:to 1 reduction, instead of the 1.15:1 reduction I am supposed to have. Meaning my theoretical maximum speed (zero slip speed) calculates out even lower than it was before, and thus my actual observed speed in the real world exceeds that theoretical maximum by even more than before, based on my RPM.

Assuming a 1.15:1 reduction they are in the -3.6 to 2.5% slip range
Assuming a 1.21:1 reduction they are in the -13 to -2.8% slip range
Clearly all that is bogus if the math is right.

Flipping that around (assuming the v-drives are backwards and acting as an overdrive using the same gears) then I think either the 1:1.15 or 1:1.21 overdrive slip numbers are *possible* with my real-life observations. But they seem like they get a little high assuming 1:1.21 overdrive gears:

Assuming 1:1.15 overdrive they are in the 18-25% slip range.
Assuming 1:1.21 overdrive they are in the 23-30% slip range.
(I'm not sure what levels of slip to hope for with old inefficient v-drive inboards pushing a planing hull in the 40-50 mph range. But I would think slip should be between 12 and 30 percent--I'd guess more like 18 to 25. The shaft angle alone, because it cannot be trimmed parallel to the line of travel, has got to take between a 3% and 10% bite out of efficiency, on top of all the other inefficiencies. I've never measured the shaft down-angle, but when up on plane, I'd think it might be close to 20 degrees, which would be about 7% loss from the vector alone, as I read a trig table.)

Mike

Ghost
07-20-2009, 04:19 PM
DING!

That was it. V-drives were put in backwards when the boat was restored under the previous owner. Instead of the proper 1.15:1 reduction it's trying to push with a 1:1.15 overdrive. While I think I would have needed the fuel system mods once the gears were set right, the gears have got to be the long pole in the tent. I think I will be underpropped once I switch the gears back to their proper orientation.

This seems to fit everything. I was pretty certain when I ran those numbers last night that the explanation seemed to fit all the symptoms. Measuring was easier than I thought. Took about 10 seconds to know it was backwards. Took about 30 seconds to count enough turns to verify the gear ratio exactly.

Now, I can't wait to get them turned around. Ugh,why do I have to have a big work deliverable this week? I wanna do it NOW. It looks like the v-drive mounts are very reversible. HOPING I don't have to do much more than disassemble, flip the housing and reassemble.

Seems like things are always harder than that, but the mounts look like MAYBE....

zelatore
07-20-2009, 05:47 PM
Well, in your favor one would assume they must be pretty easy to flip if the DPO (dreaded and/or dumb-a$$ previous owner) installed them backward without realizing.

Ghost
07-20-2009, 05:58 PM
Well, in your favor one would assume they must be pretty easy to flip if the DPO (dreaded and/or dumb-a$$ previous owner) installed them backward without realizing.

LOL, well, to his credit, I think the previous owner did a lot right with work he did himself and with work he contracted for. Also, he added a hardtop and some weight to the boat, and this may have muddied the water on what he expected in performance.

The company that did the restoration of the hull and put in the new motors and fuel tank slipped up on the v-drives. But the stringers and a lot of structure in the hull were new, cut and glassed in by them. So, as far as mounts go, they may or may not have been working from much of a template of the previous mounts. Net result: I can imagine this one going either way. The v-drives might be easily reversible without changing up the mounts, or not. Crossing my fingers...

Ghost
07-21-2009, 08:37 AM
If they are upside down, wouldn't the filler be on the bottom??

A very good question.

I see two possibilities. Either the filler plug and the breather you can see are both just plugs, and the breather can be swapped with another plug currently on the bottom. Or, perhaps more likely, I'll need to take the case apart and reverse the gears internally within it.

The gears are DEFINITELY upside down. About 7 turns of the top to 8 on the bottom. Only question is whether the case is also upside down. I need to do some more inspection to find out. Maybe a phone call will help determine whether the servicing of the v-drives during restoration included taking the housings apart.

If the gears never came out of the housings, there's got to be a way to flip the whole units over and switch the breather to the other end.

If the gears did come out of the housings, I think they just goofed and put them back in upside down. Someone else mentioned this yesterday, and it strikes me as being the more likely situation.

(Good news is this this would take any possible subtle mounting questions off the table, since the mounts were completely re-installed with new stringers and glass inside the boat.)

Ghost
07-21-2009, 10:07 AM
Make / Model V drive?

Another good question. All I have is the pic you see (with the manufacturer's plate spraypainted over), plus the restoration documentation mentions servicing the "Walters" v-drives, so probably theirs.

Lookijng at Walter Machines page, it sounds like one of theirs based on where they describe the location of the plate, and the size.

I'm going to make a quick phone call...

Ghost
07-21-2009, 10:30 AM
Sounds like they cracked them open. I'm in touch with the horse's mouth from when the work was done, and I should get some interesting info.

Now the only big question is can I get them back out. I *think* so, based on my 20 minutes on board yesterday, but am not 100%.

More updates as they come...

Ghost
07-30-2009, 12:41 PM
Okay, here's where I am now.

They DID open up the v-drives when the boat was restored in 2002-2004.

They are not Walters drives, it turns out. They are Crusader 4500s. Attached is a drawing of the outside. The yellow dots are the threaded rods that go all the way through the case, capped with nuts on either end. The dashed blue area is a mounting bracket, which as you can see from the three threaded rods it mounts on, would reverse and mount on the "top" of the v-drive case, using the corresponding rods on the other end of the case.

Hard to believe the reversal of the gears was not simply a mistake, and I can accept that, no big deal.

It appears there are two choices now.


Unscrew the breather from the top of each drive and swap them with one of the plugs from the bottom. Swap the couplings (they are slightly different top and bottom). Don't open the cases, simply flip them over and re-install. No new gaskets, no issues of fit in the case reinstalling, etc.
Open up the casings and swap the gears top and bottom. Put them back together and install with the same case orientation as before. This WILL require finding the right gaskets and such of course, to re-assemble the drive. I am assured by one mechanic that they will tear on disassembly.
Option 1 certainly looks easier, but I have spoken with one mechanic, who has been VERY gracious about taking the time to consider this with not a lot to gain from that, who believes there are channels in the case to feed lube to the bearings. He thinks the case is not fully symmetric inside, and that flipping them will starve a bearing.

But the folks who rebuilt them in 2004 say they are completely symmetric, and can just be flipped. And to me it REALLY seems like they're probably right.

If anyone knows, or knows who would know for sure, I'm always happy to get more info.

More important, if anyone knows off the top of his head where I can get the gaskets that I need, my inclination is to crack one open and find out the truth of the lube-channel debate for myself. (Presumably the folks who rebuilt them in 2004 should be able to point me somewhere, if not something they have on hand, but I'm always looking for good sources.) My gut says the debated bearing-lube-channel is not an issue, and the very kind and knowledgeable gentleman who suggested it is perhaps confusing these drives with another model. The housings appear COMPLETELY symmetric, so I have trouble imagining they'd do something different on the inside of the casting. But I don't want to bet the drives on that, of course. And I also don't want to crack them open until I have a clear lead on the gaskets for reassembling.

Anyhow, all thoughts and suggestions welcome. I'm still awaiting more word back from both shops, but just thinking out loud in the interim.

Ghost
07-31-2009, 01:26 PM
Had a nice chat with the folks who did the v-drive rebuild about 5 years ago.

They have a schematic (sending to me) of the inside and out. Says it is fully symmetric, inside and out, just like it looks. Bearings and gear cuts too. And thus, all it needs is to swap the couplers for the drive shaft and prop shaft, as well as swapping the breather with one of the plugs from the current "bottom" and soon-to-be top.

No need to open the housing and break all the seals, just to pay $100 for all the right replacements.

So, I think I'm going to try that. Maybe this weekend if I get there.

Ghost
07-31-2009, 02:17 PM
Thanks! The tags are up, so the gears did get flipped inside the housing. (I was pretty convinced of this as well, since in addition to the tags, I had trouble imagining anyone getting confused about what end was the top with the breather sticking out up there.)

What you say about the gears being NLA jives with what I've run into as well. The guys up north said they could sell me all the seals and such, but nowhere in my travels have I seen the gears. Place in Ohio sells the whole units (with different ratios) for $3300 apiece or so. And they claim to have parts. But no 1.151:1 gears.

Thanks much for sniffing around on this stuff. Now, if I get my work-work done, maybe I can do a swap this weekend. The suspense of what she'll be like afterward is killing me. My current 13x15 props should become too small and overrev. My shelved 14x16 props should also be too small, but closer to right. Got my fingers crossed that good things are going to start happening.

Mike

Ghost
08-05-2009, 12:25 AM
Long night, but one is out.

olredalert
08-05-2009, 08:27 AM
------I have Crusaders in the Fino. Looked last night and the tags are up. Mike (the former owner) gave me a spare with the boat. I appreciated it at the time but had no idea it was worth $3300. Wow!!!.....Bill S

Ghost
08-06-2009, 10:07 AM
Here's a better shot where the flash went off.

Ghost
08-06-2009, 10:56 AM
Damn, I thought the first pic was a wild turkey.. No BBQ I guess...

So, get out of the pol dicsussions and paint it, flip it, then run it and see if one engine outpulls the other.. :D :D :D

LOL, I can just see my next thread, "Boat Pulling Left"...

Just Say N20
08-06-2009, 11:18 AM
A while back you asked if I was a "closet V-drive expert" or something close to it. I had to pull both of the V-drives in my Wellcraft, and have them rebuilt to one degree or another.

I learned a few things, as I'm sure you did, having to pull one.


They are HEAVY little buggers!
Dang! They are one set of the engine mounts. How do I hold the engine up!


Nice saw horse. I'm sure there is a story about the semi-circle holes cut out of the legs. :confused:

I'm glad all of your logical consideration, and calculations eventually directed you to the problem, and the correction is doable without hooking the industrial strength Hoover to your wallet. :wink:

Ghost
08-06-2009, 01:03 PM
Thanks. It got a LOT better when I knew I could actually get the drives out without cutting any of the cockpit sole.

As for the sawhorse rig, I figured rightly that It'd be a long process of trial and error trying to get them out. Worse, I wasn't sure if I'd be entirely on my own. Some digging suggested about 75-85 pounds for each drive, and I figured nothing would be worse than not having support for in the process of trying to work out the puzzle of removal.

You can see the 4:1 mechanical advantage with the pulleys. What's hidden behind the leg that you can't see is a pair of cleats. One is a jam cleat, for rapid adjustment and locking. The second is a standard cleat, for a more secure hold. I wanted to be able to one-hand it up and lock it while doing something else. Worked pretty well so far.

(And yes, the half-moons have their own story. Those were a screwup that I had to re-cut. In the winter I save my custom cover and just eat $200/season for a shrinkwrap. I wanted it to be able to shed real snow, because the boat is up in a rack and I can't get to it to take the weight off it. So I made a wood frame to support the shrinkwrap, and part of the setup (always trying to keep from chafing the Awlgrip) was to to make a pillory--two 2x4s that sandwich the seat pedestals. The aft support bolts on the two aluminum plates on the motorbox top where the removable seatback is fastened, and the bow support sits in the stainless anchor roller bracket. Wait, maybe pictures would be better...)

I think I just hijacked my own thread...

Just Say N20
08-06-2009, 08:10 PM
I knew it! Thanks for the explanation. On both removal, and half-moons.

This proves you are much smarter than I. I get the transmission out, and wrestled into my lap (there's some fun) while sitting on a stringer, and then realize, that's as far as my plan went. :boggled: :bonk:

That is one very cool boat. And I love the fact that it is twin inboards. Very retro. I'm anxious, as I'm SURE you are to see how the boat runs with the corrected transmissions. Should be a lot peppier. :yes:

Bill

Ghost
08-13-2009, 12:48 AM
A little dizzy. Getting there though. Lots of Emery cloth in the last week, but have real hopes of running again this weekend.

Just Say N20
08-13-2009, 08:13 AM
And were they BIG circles, or little itty bitty ones? :biggrin:

Ghost
08-13-2009, 08:33 AM
OH, right, sorry, mental block. I'd forgotten about one-drive-each-way thing. Doh!

Not quite reassembling yet. Poodle guilted me into doing my best to paint everything properly. Am most of the way through that. Lots of emery cloth and wire brushing and naval jelly and mineral spirits and so on. Plus a bunch of degreasing and scrubbing in the compartments under the sole, a "might as well" while the drives are out of there.

And it's been slowed a bit due to always keeping at least 3 of the 7 threaded rods tight on each drive in my attempt not to break the seals of the housing. So that limits how much can be done on each pass and having to make more passes.

Getting there though...

Just Say N20
08-13-2009, 09:10 AM
Nice job! You are certainly thorough. And a healthy snacker, munching on dry roasted almonds :yes: . Or, using the can to hold small, misc parts.

Looks good. You will be glad you did it when you are done. And, if you are like me, if you hadn't done it, you would be kicking yourself later.

That's the attitude I have adopted since I have been doing the 16 Ski-sporter rebuild. :biggrin:

f_inscreenname
08-13-2009, 01:28 PM
Looks great, nice job of cleaning it up man! But, I am bummed we didin't get to see a vid of it spinning in circles :) :)

There is still time.:wink:

Ghost
08-14-2009, 02:12 PM
More pictures of paint drying. Tomorrow should see reinstallation and some testing I hope.

I decided to pull the drive shafts too, and clean them up and paint them. (Visible tied up with strings in one picture below.)

Also backtracked on some previous work. Was worried about galvanic issues with the stainless hardware, so I pulled the threaded rods I'd just put in, degreased them, primed and painted, and will be reassembling with those. Also painted one side of the washers that will contact the v-drive housing, and put a couple coats on the pieces of the v-drive housing where the washers seat. My goal being to galvanically isolate all the stainless hardware from the v-drive itself, in hopes of preventing any reactions that would eat away at the old beasts. (I swear that the places where stainless was used seemed like they had significantly more rust and peeling paint than the parts that didn't, so I was a little concerned about introducing even more into the system. I suppose maybe I'm imagining it, but I don't think so.) Crossing my fingers that this approach with the paint helps out if galvanism is an issue.

A little more to do yet tonight, but mostly tomorrow should be the big day. (I keep reminding myself to put fluid in the drives. Going out soon to get some...)

Just Say N20
08-14-2009, 02:58 PM
How projects expand. . . .


While you have so much stuff out, are you going to replace the crank and rod bearings in the engines?

:lol9:

zelatore
08-14-2009, 06:17 PM
Was worried about galvanic issues with the stainless hardware.........

This is the stuff we use when assembling new boats...
http://www.tef-gel.com/contain.php?param=tefgel_infor

Not sure if the paint will work - I'd expect it to sheer off from the threads while being screwed down. Certainly shouldn't hurt though.

BUIZILLA
08-14-2009, 06:19 PM
how's the rubrail? :lobster:

Ghost
08-14-2009, 09:05 PM
Good time to paint the bilge too...

Anonymous


how's the rubrail? :lobster:

LOL, you're killin' me here. Killin' me. (Actually, I thought about the bilge...)




This is the stuff we use when assembling new boats...
http://www.tef-gel.com/contain.php?param=tefgel_infor (http://www.tef-gel.com/contain.php?param=tefgel_infor)

Not sure if the paint will work - I'd expect it to sheer off from the threads while being screwed down. Certainly shouldn't hurt though.

Cool! Looks like what I've been looking for. I'm with you on the threads part, but I resigned myself to that. Actually left the threads bare where the nuts go on, and I'm just treating the threads with some anti-seize that is supposed to help with that, but not banking on it.

My scheme is all about separating the v-drive itself from the rod assemblies that go through and the washers, lockwashers, and nuts on the ends. Paint on the rods, rods well greased into the sleeves, hoping the paint and grease keeps the rods from direct contact with the sleeves. Then several layers of paint between the v-drive case and the washers/lockwashers/nuts. With the flat washers down against the painted case, I think the paint is doing fine underneath, just being compressed when the washer seats, but the washers don't spin, and so I think the paint is staying intact.

I figure the rods themselves may react with the nuts and washers, but all that is replaceable at the HW store for $100 in a few years, whereas the circa 1970 Crusader 4500's are more dear. They die and the motors probably get spun around and duopropped, and we go that much further to resto-mod.

And, as you say, it certainly won't hurt. WTF, and it should be better than it was. I think.

Thanks for the tip on the tef-gel though. I have a feeling I may find lots of uses for that, even if I missed the deadline for using it here.

Mike

Ghost
08-17-2009, 02:12 AM
So, I only got her in the water by about 1:30 today, and logistics precluded swapping props yet. I wanted to try the ones I knew, to isolate any vibration issues or anything that I might have done wrong in reinstalling the driveshafts and v-drives.

Here they are going in.

http://img30.imageshack.us/img30/3612/19677579.jpg
http://img40.imageshack.us/img40/9969/92147581.jpg

The newspaper isn't pretty, but after all that scrubbing in the bilge, I didn't want the new grease to ring the compartment, and I wanted to easily SPOT and catch any leaking gear oil. Both of these paid off already.

Here are a couple of shots installed. They sure LOOK better, compared to the BEFORE shots. Glad I took the time to clean up and repaint the driveshafts. And I'm getting to know my boat better and better. But the speed results were disappointing.

BEFORE:
http://img257.imageshack.us/img257/4219/73296893.jpg
http://img16.imageshack.us/img16/4275/51719366.jpg

AFTER:
http://img20.imageshack.us/img20/83/33802166.jpg
http://img20.imageshack.us/img20/6708/90513508.jpg

I think the drives are okay. Heard a few things that sounded funny to me here and there, but the cooler was bouncing around, and as silly as it seems, it was hard to know what I was hearing sometimes. Definitely sounded different in some ways. Also got a little leakage along the seam in the v-drive cases. One actually dripped a few drops, the other just showed oil on the seam. I had deliberately not overtightened all the threaded rods, and they were probably just not tight enough. I snugged them down a bit at anchor and saw no more hint of leakage.

Amazingly different in some ways. Hole shot was much better. I never pushed it too hard before, in part because it felt too laborious. Pushed it hard once today and hardly even saw any bow rise she came out so fast.

RPM went up to the 4800-5200 range. But a bit disappointing. Speed went up about another three-quarters of a mph, but that was it. But it was not a good day for speed runs either. Traffic and awful chop meant only being up at WOT for about 5 or 10 seconds at most. But still, I was hoping to see the engines jump up to their 5000RPM max rating with some room to spare on the throttles, and I didn't see that. All with just the little 15 inch props still. In the next day or so I will try a prop swap. Who knows, maybe I will need to start looking at alignment/carbs, etc. But the work I just did should be good for the boat, and it definitely had to be done on the road to getting the speed right.

I'll try the 16 inch props next and see what happens, but I am only expecting to see the RPM get knocked down a little, and about the same top end, 45 mph or so.

BUIZILLA
08-17-2009, 06:30 AM
big A for effort on the snatch block hardware.... very clever..

zelatore
08-17-2009, 09:38 AM
big A for effort on the snatch block hardware.... very clever..

I hear he's a closet blow-boater...

Ghost
08-17-2009, 10:46 AM
big A for effort on the snatch block hardware.... very clever..

Thx, that setup was worth its weight in gold. What's hard to see is the bizarre sequence of drop a little, rotate a little, slide this threaded rod, drop a little, rotate a little, slide these rods, go back up a little, etc. It was like a chinese puzzle to get them in because they were glassed in with a smaller hatch than the stringer width. The process of getting them in without beating stuff up took maybe 25 minutes before they were secured to the mounts. Don't think I could've done it without my poor-man's crane.


I hear he's a closet blow-boater... LOL, I was mostly rail meat--in it for the beer. "What?! We've gotta tack again? Can't you just figure out which way you want to go?"

Ghost
08-17-2009, 11:49 AM
I haven't yet seen the results I'd hoped for. Better, and another thing that needed doing, sure. And I need to take some better measurements, with my current 13 x 15 props, and also with my 14 x 16 props. So far it looks like I only picked up about 1 mph, if that.

But, thinking abstractly for a minute, anybody know how a dyno test works? I assume the dyno varies the LOAD on the engine, until a specific LOAD is found where the engine, at wide-open-throttle, pushes that LOAD at a targeted RPM.

Two specific questions relating to this:

1. So, if I dyno'd my engines, they'd vary the load until they found how much LOAD my engines could push at say, 5000 RPM. From this LOAD they would derive a horsepower calculation. Sound right?

2. Before my v-drive adventure started, the LOAD was too great, not optimal for the engines, and my RPM maxed out at 3600 or so. Now they appear to be getting up in the 4900-5100 range. I assume this means I am getting some more HORSEPOWER out of the engines. (Even if it is only a little more, it has to be more horsepower if the manufacturer's WOT RPM spec was properly chosen at 5000 RPM). Is this correct?

Thanks for all thoughts/experience on this. -Mike

MOP
08-17-2009, 12:39 PM
It is good to see you are getting it together, there is always fiddling near the end.

Keep up the great work!!!

Phil

Ghost
08-26-2009, 07:17 AM
:) Yeah, kind of a mixed bag. I got a chance to do some proper testing this weekend, with good water. I'm up another knot even though the port motor is not very happy. The v-drive part of the system seems fine, no issues there best I can tell. Starboard motor is turning 5100 even while pulling the other along. The port engine is only doing about 45-4600, and the tach seems *quite* jumpy. I think I need a tune up or something. I peeked at one of the plugs, which are only one season old, and it looked okay to me. I replaced the distributor cap and rotor, which didn't look so hot to me, but that didn't change anything. I suppose distributor wires *could* be a problem, but that seems unlikely to me.

I've heard rumors about another set of fuel filters besides my Racors, but I don't see them anywhere. There's a condenser and one other part that came with the distributor cap, which I guess I need to try. My fuel tank has been sitting pretty low for a while in this high humidity, so maybe I should try to bleed off the Racors. Or who knows, maybe I need to do serious carb work. I'm kinda grasping at straws right now, and appreciative of any advice. If both engines were pulling like the strong one, I think my RPM woud reach 52-5300 on both, and I'd switch props. But right now, I'm kinda scratching my head. I called PCM to get a proper owner's manual so I can gap the plugs properly and such, but mostly I am trying to figure out what to try next. I guess I could start swapping parts from one motor to the other.

All ears if folks have ideas of what to test or what to try...

f_inscreenname
08-26-2009, 09:18 AM
I guess I could start swapping parts from one motor to the other.

All ears if folks have ideas of what to test or what to try...

I would try the carb first and maybe the fuel line. Was talking to a buddy and the first thing he said was a fuel issue with the jumpy tach.

zelatore
08-26-2009, 09:25 AM
Assuming you have Racors with clear bowls at the bottom, you should have no problem seeing if there's any water in them. A few drops will look like beads floating in the bottom, while more will create a clear separation layer. The only time I haven't been able to spot water in a Racor quickly was when there was so much it filled the entire clear bowl (!).

That said, I don't think water is your problem.

f_inscreenname
08-26-2009, 04:08 PM
Tachs are electric, how does fuel affect them?


I'd be checking ignition..


I think there is a fuel filter on those engines, bowl type, not real efficient if I remember correctly. May even be a cleanable element...


Sorry, from another board :wink:. G can also feel the motor surge so we think the tech is good.

Ghost
08-26-2009, 04:53 PM
I need to thoroughly trace the fuel lines. It seems crazy that I can't just say whether there is a filter downstream of my remote Racors, but it's really tight under and behind the engines, so it's harder than it might seem. I took a rushed look the other day, only had a minute, and snapped a bunch of pics with my digital camera (a method that has worked well when I can't get in a position to see something) and I didn't find anything. But I was rushed, and I could have missed something.

I did get a picture of a fuel pump (see below). I am assuming it is just a pump, and has no filter inside, but correct me if I am wrong about that.

I had a VERY brief call with Pleasurecraft to get a new owner's manual, and tried to get a question or two in with them, but to little avail. What they did say is that there was not a filter with the motor as it came from them, so whatever the manufacturer put in is what is there. Since this was a repower, that would mean whatever the folks doing the restoration did.

But oddly, the previous owner definitely said there was another set of filters besides the Racors. I hate to bug him but I guess I might do that to ask what other filters he meant.

BTW, the tach is jumpy like the motor is running roughly. The swings in RPM are small jitters, not larger swings. Maybe between 3 and 8 oscillations per second and far less than 100RPM in variation, more like 10 to 30 RPM maybe. Up at WOT, the motor does not hold a steady RPM, and the tach drifts up and down over wider ranges, maybe 100 or 200 RPM, I don't think it is as jittery (but won't swear to that), and seems to me like it is consistent with changing RPM (slightly more or less speed, etc.) So I THINK the tach isn't lying to me, and the motor is just running roughly and not achieving full power.

Ghost
08-26-2009, 07:21 PM
LOL, indeed.

Ghost
08-26-2009, 10:41 PM
The bottom is just barely out of view in the pic, and has a couple wires and a wiring harness coming out of it. I'll try for another pic, but I think this is pretty close. Nothing I've seen about it on the net suggests to me there is any sort of replaceable element inside, but who knows.

Ghost
08-27-2009, 12:32 AM
Found a pic where you can see the bottom of the pump.

Also, wondering how long plug wires should last...and how long before a carb rebuild is typically needed.

http://www.donzi.net/forums/attachment.php?attachmentid=49878&d=1251351160

f_inscreenname
08-27-2009, 07:27 AM
Just a FYI
I use one of those clear inline filters up near the carb in the 19. It has a new (couple years now) plastic gas tank, new lines to and from, new filter/separator and you still should see all the crap this thing picks up. I have to change it at least twice a season but the carb stays clean. And I use regular gas stations. For as much as it costs, gas sucks.

BUIZILLA
08-27-2009, 08:00 AM
is that plastic tank ethanol friendly? or is it melting inside...

f_inscreenname
08-27-2009, 09:29 AM
I guess I shouldn't have said plastic...... its fine.

Ghost
08-27-2009, 10:42 AM
I only give plug wires about three years at most. You can ohm em out if you want.

Surging would tend to indicate fuel IF it is a smooth surge. With todays crap fuel, carb rebuilds are going to become more frequent. The Racor is the best thing you can do for your boat, but keep in mind one that dirt can plug them even though the bowl looks clean. You could install vacuum gauges on them to keep tabs on the element, we do on our larger engines..

Well, maybe plug wires do need a look then. (Mine are probably at least 7 years old from the factory, with about 5 fairly light seasons on them.) Last night I came within an inch of ordering one set so I could at least test their resistance and compare that to the ones on the boat. (Shelve them if they're fine, install them if not.)

Plus I need to look and figure out whether I even need a new condenser and points, as I honestly don't yet know if my system even has them. I do know my distributor cap and rotor pretty well now, but not the rest. And I double-checked the firing order, which was fine. (I'd have thought I'd have REALLY been able to hear a problem there, but checked anyhow.)

Funny, I also came within an inch of buying vacuum gauges for the fuel lines when I put in the Racors. In my ideal world, I'd do those, and maybe even put in 4 filters and valves to allow swapping them out at sea. Short of that, maybe the vacuum gauges alone would be smart.

Not sure I would call this a smooth surge--maybe the stuff at WOT seems more like this, but at lower RPM it's not a smooth thing at all, just looks like the engine cannot find a stable RPM, and it sounds a little rough to my untrained ear.

Now that you've seen the bottom of the fuel pump, think there's a filter element inside? (I'm thinking no, as much from the lack of signs of replacements for it as anything.)

Ghost
08-27-2009, 11:53 AM
No, that vane style pump is supposed to have a primary filter before it. Is there any sign of a ilfter after it?

I will look again, but I think not. I believe the rigid tubing leaves one side of the pump head and goes through three 90-degree bends as it makes its way up to the carb, and that's it.

f_inscreenname
08-27-2009, 12:09 PM
Well, maybe plug wires do need a look then. (Mine are probably at least 7 years old from the factory, with about 5 fairly light seasons on them.) Last night I came within an inch of ordering one set so I could at least test their resistance and compare that to the ones on the boat. (Shelve them if they're fine, install them if not.)

Plus I need to look and figure out whether I even need a new condenser and points, as I honestly don't yet know if my system even has them. I do know my distributor cap and rotor pretty well now, but not the rest. And I double-checked the firing order, which was fine. (I'd have thought I'd have REALLY been able to hear a problem there, but checked anyhow.)

Funny, I also came within an inch of buying vacuum gauges for the fuel lines when I put in the Racors. In my ideal world, I'd do those, and maybe even put in 4 filters and valves to allow swapping them out at sea. Short of that, maybe the vacuum gauges alone would be smart.

Not sure I would call this a smooth surge--maybe the stuff at WOT seems more like this, but at lower RPM it's not a smooth thing at all, just looks like the engine cannot find a stable RPM, and it sounds a little rough to my untrained ear.

Now that you've seen the bottom of the fuel pump, think there's a filter element inside? (I'm thinking no, as much from the lack of signs of replacements for it as anything.)

7 Years? Change them no matter what.
And if you still have points you need a Pertronix kit and throw them away.

MOP
08-27-2009, 08:03 PM
Not sure if I am rehashing things, have you checked the filter in the carb fitting, also have you checked the float levels. Just a hunch sounds like the carb is running low on fuel.

Ghost
08-27-2009, 08:11 PM
Not sure if I am rehashing things, have you checked the filter in the carb fitting, also have you checked the float levels. Just a hunch sounds like the carb is running low on fuel.

Thanks. I have not checked anything in the carbs. My first look at the carbs was going to be to let the motor warm up, pull the arrestor, and see if the atomizing looked good (aka: looked hard to see) versus looking like there is fuel dripping down in there. Somebody recommended this to me.

Don't know what filter you mean "in the carb fitting", mostly because I don't know jack about carbs yet. Not sure how to check float levels yet either.

Ghost
08-28-2009, 06:25 AM
Pics of carbs?

"Sometimes" in the fuel inlet fitting you will find a small sintered bronze filter..

Thanks, I will try for some pics today/tomorrow and post them.

f_inscreenname
08-28-2009, 07:05 AM
Oh my damn! I never thought of that one. I don’t have them in the carb's I run.
Screw the pictures and unscrew your fuel line off the carburetor. There is a filter back there.
I feel like such a jack ass. :bonk:

Ghost
08-28-2009, 11:16 AM
Oh wow, thanks. Check that lil dude out. I guess you just get him out and soak him in carb cleaner, from the look of him? (Meaning you don't generally replace it, unless a carb rebuild kit comes with a replacement, and you normally just clean the existing filter up.)

zelatore
08-28-2009, 01:17 PM
For testing purposes I would just leave it out. You've got the racors up-stream anyway. You can pop those suckers out at the dock and be testing in 15 minutes.

f_inscreenname
08-28-2009, 01:46 PM
I don't use them. Restricts fuel flow.

Just Say N20
08-29-2009, 08:26 PM
Well?????????????????????????????????????????????? ??????????????????????????

I think he's been busy writing a thought provoking dissertation in another section. :wink:

Ghost
08-29-2009, 09:15 PM
Had other commitments today (was lucky I had time for the gutter).

Maybe tomorrow if I am lucky I will get a chance to try a little. Have a BIG deadline on Friday and won't have much time between now and then. (And then I'll be down there just north of Cuba for a week...)

f_inscreenname
08-29-2009, 10:14 PM
Let me know when your down thisaway, I'll try and break free for lunch or sumthin :)

And get him to bring his photo album with him.:yes: And maybe a color copier with photo paper. :wink:

Ghost
08-30-2009, 12:09 PM
Let me know when your down thisaway, I'll try and break free for lunch or sumthin :)

Cool, I'm definitely up for that if logistics will work for you. We fly into Lauderdale on Saturday and will be driving down to Key West at our leisure. Driving back up and flying home the following Friday.

Did some more testing today.

I've pretty much replaced all the ignition in the port motor but the plug wires, and I have those coming this week.

I got what I think are the right gap specs for the plugs, and I put new, properly gapped plugs in the port motor this morning, replacing the ones in there from last year, to be sure.

opened up the carb where the fuel line comes in and it didn't have the little brass filter in it, so pulling that filter wasn't part of my test today. Looks like it would go right in the cylinder there, just no brass filter and spring to be found. I wonder if somebody pulled it a while back.

I THOUGHT it was going to be a big change when I first got out. The jumpy needle on the tach stopped being so jumpy. And I slowly got out and increased speed, 3000, 3500, 4000, 4500 with plenty of throttle left on BOTH motors. Here I was thinking I had it, and it was the plugs.

When I pushed the throttles all the way forward, the port motor went up nearly to 5000, certainly 4900. For a bit. Then it started to fall off, and wouldn't stay up there.

Several successive attempts at WOT repeated the pattern, with worse results each time. The port motor didn't get as far as 4900 again, instead topping out at more like 4300-4500, and once it topped out, it started to fall fairly quickly, down to like 3000 the first time, lower the second, and all the way down to a full stall the last time.

After that I was still able to run the motors up to 3000 and cruise. I didn't push it past that, but had no signs of trouble.

I have a couple of theories now, but will keep my mouth shut for a bit and try not to put ideas in anyone's heads.

olredalert
08-30-2009, 07:53 PM
------Baxter sounds correct and if the engine is running out of fuel its running too lean as well. Very bad to run lean for too long........Mr.Bill

MOP
08-31-2009, 08:21 PM
Have you checked the float levels?

Ghost
08-31-2009, 10:29 PM
Have you checked the float levels?

Nope. I need to start learning about carbs--don't know squat right now. Sadly, I have a crazy next two weeks, and won't probably see the boat again until mid September. Thanks for pondering this--I appreciate the help and apologize that I won't be able to give much feedback for a while.

Mike

Ghost
09-29-2009, 01:59 PM
Getting back to this a little. Hoping by this weekend, next at latest, I can actually visit my boat again...

First, the plugs definitely smell heavily of gas, which I am told is definitely NOT right, and may indicate I have a too-much-fuel problem instead of a too-little-fuel problem.

Second, recall the "winding down" behavior up above, where the motor ran okay at cruise RPM, but when pushed wide open it didn't quite get as high as it should, and then started falling off. With each successive try, its peak RPM was substantially lower, and by the third or fourth try, it wound down all the way to stalling out.

Could the "winding down" behavior be a result of flooding, where the spark (for whatever reason) was not able to ignite the fuel when up at high RPM, which was leaving residual gas in the cylinder after the exhaust stroke pushed most of the uncombusted air/fuel mix out?

IF the winding down could be the result of this, I have two theories as to why it might happen.

First is a purely carb problem, where the mixture is too rich, and where that becomes a problem at high RPM. (But honestly, I don't know why running rich would not be noticed up to about cruise RPM, and then would become an issue up nearer to WOT RPM, unless it were *combined* with a spark issue, which is my next idea.)

Second theory is a weak spark problem, where the spark is just barely enough up through cruise RPM. But up near WOT RPM levels, the weak spark is no longer enough to ignite the mix consistently, and missing starts to occur. And each miss in a cylinder makes that cylinder more likely to miss the next time, as some residual fuel is left from the last cycle that didn't ignite. Once a peak RPM is reached, it would fall down quite a ways until it reaches an RPM where the spark was strong enough again, and then it could burn off the residual fuel from the misfires and stabilize. (Unless there was just way too much residual fuel to deal with, where it would fall all the way down and stall, and then restart a bit later, like any flooded engine.)

This strikes me as fitting the symptoms, but would likely depend on two things about engines I just don't know:


First is, is it easier or harder (or neither) to ignite a richer-than-ideal stoichiometric air-fuel mixture? I would think it would be harder to ignite, but I am not certain of this.
Second, is it easier or harder to ignite an air-fuel mixture when it is more compressed? I would think it would be easier to ignite an air-fuel mix, the more compressed it becomes (on the way toward igniting without any spark, like a diesel). But I don't know.
If my two assumptions above are correct, I have a theory. Could a borderline weak spark be just strong enough to light the mixture up to cruise RPM or so? And then, as the RPM climb, could the ignititon timing advance require that already-weak spark to detonate a mixture that is less and less compressed by the piston (and thus harder to ignite), to the point where the weak spark is no longer enough? At which point, the problem would make itself worse and worse, because more and more residual fuel from misfires fouls the cylinders, and the engine winds down?

Or, is there any other basic engine trait I am missing that requires a stronger spark at high RPM?

That may be completely nuts. As I say, I don't know much about engines. But I'm trying to take the symptoms I have and see if something fits. The two things that seem most important to me in this winding down are that the problem seems imposed by increasing RPM, and that the plugs DEFINITELY reek of gas.

All thoughts welcome, thanks.

Mike

zelatore
09-29-2009, 06:28 PM
Other than smelling badly of gas, how did the plugs look?

BTW, I'd suggest replacing the plugs regardless of how they look. Plenty of times I fuel-fouled a plug and despite cleaning it to where it looked OK, it still mis-fired.

Ghost
09-29-2009, 08:03 PM
Other than smelling badly of gas, how did the plugs look?

BTW, I'd suggest replacing the plugs regardless of how they look. Plenty of times I fuel-fouled a plug and despite cleaning it to where it looked OK, it still mis-fired.

The old plugs had about a season on them and it was hard for me to know what to say about their appearance. I couldn't tell anything certain when I compared them to the common series of plug pictures (about 10 pics of plugs, one normal and the rest with issues.) Closest pic I would say was the normal one, but I think those pics show extremes over a long time, and mine were only a year old.

Long story but the short version is that I replaced one plug recently as a test, before replacing the other 7. All smelled of fuel when they came out, including the test plug which went in new a few running hours before its brethren, and which I pulled to visually inspect when I put the other 7 in.

Engine power was below what it should have been BEFORE the plug change, and probably worsening with time. The "winding down" events happened right after the plug change, so the plugs were brand new and nicely gapped to Pleasurecraft's spec. On the trips before the winding down event, the RPM maxed out maybe down around 4600, and I didn't let it stay there for very long.

Right after the plug change, the first attempt to open it up saw nearly 5000 RPM as the peak, then a wind-down. The next one peaked lower, maybe 4700, then another wind-down. Then even lower peaks after that in the last couple of attempts, before the wind-downs started.