3800 Max Rpm's 454magMPI

[CJmike]

I got something going on with the 27zx and I can not get the boat above 3800 rpm's. Boat also seems rather slugish. Any body got any suggestions as to what I should be checking?

At first I thought it was a prop issue but now I am thinking it is something motor related.

I did have a seawater pump eat itself and the motor did get a little warm before I noticed guage was still reading around 180 when I shut it down. The exhaust boots on the other hand got a little crispy. I did change the oil after this and it didn't look bad.

I need to change the fuel filter and see if that is plugged or something.

[RedDog]

I'd say fuel filter. Drain it into a glass and look for water.

[Pismo]

Fuel restriction someplace.

[CJmike]

Fishing lure in the fuel filter?

Looks like a rubber worm in my fuel filter when I pulled it. Put a new one on tomorrow and hopefully take it for a spin if the weather gets a little warmer.

[cutwater]

I'd say fuel filter. Drain it into a glass and look for water.


Fuel restriction someplace.

Good call(s), apparently. The old lure in the gas tank trick. If I had a dollar for every time I fell for that... Wait, a lure in your gas tank?? :bonk:

[The Hedgehog]

That is crazy. Sounds like someone pulled a mean joke on big boats. I hope that you have not been harassing fishermen up there in the great upper midwest! And I sure hope that nobody down here did that:crossfing:

My mechanic found a leaf in my oil filter pickup of my 502. I will try to dig up a pick somewhere. Go figure

[CJmike]

Guessing it happened in TN before I hauled it home. Since its been in Minnesota it has just been sitting in my yard. No big deal and it does explain the performance loss since it has been in MN.

[CJmike]

Well changing the fuel filter got me closer to 4000 rpm but not a dramatic change. Still around 45 mph speed. No real change in RPM from 2/3 to full throttle.

[The Hedgehog]

If that fixed part of the problem, it sounds like a fuel pressure issue. There should be a shrader valve on the front of the fuel rail. A pressure gauge rigged up to a shrader valve connection can be used to verify the pressure. I am not totally sure about the 454 but it should run a constant 37 psi on a 502 MPI.

From what I remember on non-blown engines, you can hit the key and it should hold that pressure. Then you can start it and run it up and see if it holds. You will have to run in under a load (in water) to see if you are having those issues.

[glashole]

that gain of 200 rpm is minimal I think you need to keep looking

does it rev out when it is on the trailer or in neutral or just under load?

have you ever had the boat revving above those numbers personnally?

might not be a big issue but is there fresh gas in the boat right now?

[RedDog]

If you found one rubber worm, maybe there are more?

[CJmike]

Yeah boat ran great when it I first picked it up down in TN. Ran up to 55 at that point I didn't pay a bunch of attention to the rev's as I was just getting used to the boat.

On the fuel front. Filled it in TN and hauled it home. It sat for maybe four weeks. The boat sat when we got back with 3/4 of a tank. Then we topped off the tank and ran a day. Then it sat for another month and then we got out a few days. Then it was topped off and sat for a week till we got out again this week end. So while the fuel is not completly fresh its not what I would call old. Each time I filled it since TN I have put about thirty gallons in. I leaning towards running it down at this point to take the bad gas out of the equation. I could just drain it down and run the fuel in my vehicles.

Also on a 454 Mag MPI does octane matter. I am running to low of ocatne at 87 octane? Last time I topped off I put in 89 octane. Maybe the knock sensor is retarding timing becuase I am running to low of octane.

To me it feels like a fuel issue as it doesn't seem to be supplying the fuel to support the top end. At least that was my thoughts after the run last night once I could rule out a dirty filter.

[The Hedgehog]

You have a MEFI 3 on that system. It is pretty good (the same that they use in the 500EFI) but with that C/R you should not be getting knock unless you have bad gas. The boat has a stock tune (nobody has been into the ECU) so you should not be getting any lean out.

I am scratching my head but it still sounds like a fuel or fuel pressure issue.

[osur866]

How about throttle linkage is it opening up all the way. Steve

[DON N.]

THERE ISN'T WATER IN THE BOTTOM OF THE BOAT IS THERE ?:shocking:

[CJmike]

Throttle is opening all the way. That is one of the first things I checked.

Making sure the bilge is dry. The boat is trailer kept now so everytime it comes out of the water the drain gets pulled. So thats not it.

Suppose to rain for the next few days so most likely I won't get to check anything till Sunday when it is suppose to be nice.

Any chance a restriction or drag in the drive is keeping me from getting into higher RPM's. I know it was suggested earlier to rev it with out the drive engaged but haven't had a chance to try that yet.

[MOP]

Everyone seems to forget the basic rule, any drop in power the very first thing is to pull the plugs look for discoloration. If they are light in color fuel is restricted, if they have a red tinge there is water intrusion. I can not understand why most will keep running an engine that has an obvious problem and not pull the plugs as there very first part of the diagnosis! Back to the rubber worm, if you found one in the filter there is no anti siphon valve in the fuel pickup no way would it pass a rubber worm! The worm you found is probably one of several, that can cause you grief until you can get them all out. Your only recourse may be to pull the tank.

[BUIZILLA]

is the transom sooty?

[MOP]

is the transom sooty?

Jim the problem with soot is it can be left over from when it was running good.

[BUIZILLA]

that engine was notorius for injector and fuel regulator issues...

trust me on how I know that...

[CJmike]

Have not pulled the plugs but I will pull and check the condition.

Transom is not especially sooty. But I wouldn't have a clue how sooty it should be.

[Jamesbon]

Pull plugs, do compression test, if all is normal, have someone plug into the "brain" with a Merc. scan tool and check for faults. Good luck.....

[mrfixxall]

Have not pulled the plugs but I will pull and check the condition.

Transom is not especially sooty. But I wouldn't have a clue how sooty it should be.

Did you winterize the boat? Did you fog the engine? if so you probably have a fouled sparkplug from the engine fog. one cylinder not fireing and you will be down 400-600 rpms.one thing about a big block is its hard to tell if its missing at idle if your not familar with the noise it makes..

[CJmike]

Plugs all looked good except one which was little darker. Not a bunch just not the same as the rest. Maybe getting a little blow by on that cylinder. But certainly not off enough that it would worry me.

I pulled the cap and rotor quick before the rain started in again. They don't look as nice as I would like. Probable replace them tomorrow as the part store is closed now.

Fuel pressure at first cycle of the key is at right around 40. Of course the gauge I have has the wrong fitting on the end so I just checked it with a pencil style. Need to get the correct sending unit for the gauge in the dash or get the correct fitting for my portable gauge. Bill you got the part # for the sending unit that matches the gauge?

Rechecked the fuel filter for water or any more gunk and it look crystal clear and I got nothing but gas in the glass.

[The Hedgehog]

Plugs all looked good except one which was little darker. Not a bunch just not the same as the rest. Maybe getting a little blow by on that cylinder. But certainly not off enough that it would worry me.

I pulled the cap and rotor quick before the rain started in again. They don't look as nice as I would like. Probable replace them tomorrow as the part store is closed now.

Fuel pressure at first cycle of the key is at right around 40. Of course the gauge I have has the wrong fitting on the end so I just checked it with a pencil style. Need to get the correct sending unit for the gauge in the dash or get the correct fitting for my portable gauge. Bill you got the part # for the sending unit that matches the gauge?

Rechecked the fuel filter for water or any more gunk and it look crystal clear and I got nothing but gas in the glass.

gaffrigperformance.com/Products/gauges.cfm?theSubCategory=16

There is where you can find the sending unit. I used this gauge as more of a proxy. It is not as accurate as a full mechanical. The sending unit was mounted on the fuel pressure regulator that Procharger supplied. You might be able to hook it to the rail.

Those caps and rotors get surprisingly nasty in short time. From what I remember the same cap and rotor as a mid-90's 350 truck engine works. I can verify that if you like.

I don't know if it it the source of your issues but it probably would not hurt to replace them. You should probably do it anyway. I did that when I bought a boat and picked up 300-400 rpm. You need to follow the fuel pressure as power climbs.

It is good to know that it is good at idle but you need to know it holds. I spent a bunch of time looking over my shoulder doing this when I dialed in the procharger.

[CJmike]

Replaced the cap, rotor, and spark plugs this morning. Distributer shaft was pretty corrided under the rotor so I cleaned that good. Parts place didn't have the fuel gauge I needed but I ordered it and it should be here Monday afternoon. Maybe able to get the boat on the water later today or tomorrow and see if the tune up helped. If not wait for the fuel gauge to get here and see whats going on with the fuel system.

[DonziJon]

Are the spark plug wires "Talking" to each other, or to the engine block? Start up the engine After Dark and look for plug wires arcing every which way. Wires could be getting old.

Another quicker way to check for leaking plug wires is to wet your thumb and index finger and grab each wire one at a time and see if you get a Jolt. :smash: Don't use this method if you have heart problems.

[CJmike]

No change with the plugs, cap, and rotor. Fuel pressure guage should be in tonight. Then back on the water to test fuel pressure.

[mrfixxall]

When you get the boat back into the water,get yourself one of those sparkplug boot plyers abd set youe engine rpms at 1000 and pull each plug wire and lister for a change in the engine then reinstall the plug wire,if theirs no change in the cylinder you remove the plug wire fron then that would be the problem your having...Buiz is rite those injectors are a problem from the get go! If you find a cylinder that isnt firing then move to the injector on that cylinder(if you can get at it)with the engine running and the injector is accesable take a long screwdriver and put the handle to your ear and the blade pare of the screwdriver to the body of the injector..if you hear the injector clicking its working but their may not be fuel going through it though,now the hard part, remove the upper intake plenum to access the injectors,remove the four injector rail bolts and remove the injector rail and injectors..remove the injector retaining clip on the injector thats not firing and pull the injector from the fuel rail,,look into the center of the injector and look into the center of it (where the fuel goes through center)alot of times the screen gets plugged with crap and wont allow the fuel pass through the injector..sometimes you can use carb cleaner to clean the screens or find a fuel injection professional that back flushes and checks the fuel pattern to do this for you..

[CJmike]

Finally got the boat on the water again this weekend. Still only 3800 rpm's when in gear. Put the boat in neutral and ran it up to 5200. Also had gotten the fuel pressure gauge hooked up and it was pretty steady at 38 psi at idle and 42 psi under full load. I think I can rule out the motor being the problem. Maybe time to start looking at the prop or the drive.

[CJmike]

Dropped the boat at Valley Motorsports in Egan today to have them look at it.

[CJmike]

Bad compression. High 120 low 100. Need to do a leak down and see if its the rings or the valves.

[mrfixxall]

Bad compression. High 120 low 100. Need to do a leak down and see if its the rings or the valves.

Tell them to do ut with the engine warm and with the throttle fully open,betcha the numbers go up!

[MOP]

How many hours have you run it since its last layup and was it fogged out?

[CJmike]

Not sure if Bill fogged it last winter before he put it up. I am guessing he did. I have not had it sitting for long enough to have needed to fog it since I have had it.

I am guessing the shop knows what they are doing when it comes to this stuff. Nothing but Go Fast boats in the yard.

[mrfixxall]

Not sure if Bill fogged it last winter before he put it up. I am guessing he did. I have not had it sitting for long enough to have needed to fog it since I have had it.

I am guessing the shop knows what they are doing when it comes to this stuff. Nothing but Go Fast boats in the yard.

ALot of techs thease days are lazy! ive whitnessed it myself.. Start the boat and get it hot then have to work on a hot engine and hot sparkplugs! i myself being a performance auto and marine hate working on hot engines, but to get the honest readings i have to.:)

If you had weak cylinders it would crank really fast or if you had one weak one you would hear it when cranking the engine over..
Mabe your timing chain skipped a tooth,that would give you low compression and if the readings you have are correct..

[The Hedgehog]

It had good compression in the fall and ran well when Mike and I ran it for the sea trial. I set the boat up for a few weeks but did not fog it again. I did fill the cooling system with anti freeze. Mike had another good trial when he got it and ran it for a couple of days in Tn before heading back to Mn. It ran well again.

He went back to Mn and then it lost about 10 mph. I have spent some time in the Upper Midwest and found the folks up there are pretty fun people. I felt sure that the Green Donzi would be happy up there. I am wracking my brain on what could have changed.

From what I have been told, MrFixx is dead on about the testing on hot motors.

[Cuda]

Bad rings won't make much of a difference in compression. My first car, I bought $1 worth of gas, and $1 of engine oil a day, but it still had good compression, even though the rings were worn out. Unless you have a hole in a piston 5 will get you 10 that if you have low compression, it's a valve problem. Even just a little rust around the valve seats will make a big difference.

[CJmike]

I am guessing this all boils down to sea water pump eating itself up here in MN. Even though the temp guage showed a decent temp I don't think it had fluid in it to get a good reading. Performance has been down since. If it just the valves we will pull the heads and redo them. If its the rings it will stay togther for the season and then get torn down this winter.

I talk to the guy when I pick it up to see how he did the test. But when I talked to him first before lunch he questioned me on problems and then said they were going to run it on their dyno. Later he called me with the news on the compression. I am guessing by the time frame involved it was a warm motor when he did the compression test.

These are the guys I took it to.

http://www.valleymotorsports.net/

[BUIZILLA]

your not going to lose 30-40 psi of compression in all the holes, just because you drove it to another state... get another opinion

[BUIZILLA]

your still not going to lose that much pop getting it hot.... crack the heads, maybe...

loose that much pop without cracking the heads...

noper's

[mrfixxall]

New Mercury/Mercruiser Dealer!

Hmmmmmm! they must be new at this stuff:)

[VetteLT193]

Could it be elevation difference? I don't imagine there would be much difference between TN and MN but I thought I'd try a different perspective.

I agree with Buiz, it doesn't make sense to have those numbers... get a 2nd opinion.

[CJmike]

Got my motor guy coming over next week some time. We'll do a leak down test for sure. Maybe rerun the compression test if he wants. Would do it this weekend but he has some commitments with the inlaws already.

[TREYSTJOHN]

First thing we do after overheat before everything else is a compression test and a leakdown test to determine basic state of internals. Have you done a leakdown test to determine valve condition. My guess is you have leaky valves or have killed your rings due to overheat.

[Dave_N]

If the problem started when you had a seapump failure, I would suspect that you burned an exhaust shutter and it dropped into the Y pipe, causing an exhaust restriction.

[CJmike]

No y-pipe straight out thru hull.

[Last Real Texan]

Has any one hooked this up to a scan tool yet? if so what codes has it set? No water in the oil or in the valve covers either , could be a head problem but it is really difficult to tell with out the leakdown test done. You say they at Valley motorsports ran it on there dyno? what kind of dyno is this? propshaft hook up or what? I think you did the right thing by removing the boat from them and getting some on to really check it out. After all this is a stock motor and it should not be that difficult. Back to the worm theory....have you run it on a slave tank to isolate that there is not one in the botom of the tank blocking the pick up? or at least pulled the pick up to see if it has a worm stuck in it? My guess is it is an electrical gremlin that may some how have something to do with the overheat....pehaps a wire somewhere or a sensor got fried and is causing you some poblems...again run a scan tool on it. But hey this is just a guess and that is the last thing you need right now.

Good luck :smash:
Tex

[CJmike]

Valley Motorsports hooked it up to a propshaft dyno. The motor threw no codes. He did the compression test hot. I have all the cylinder readings out in the truck I'll post them later. Next comes leakdown test. He would have done them if I had asked but the main reason I took it there was to get it scanned. Didn't want to spend anymore money than I had to at the shop. The guy appears to know what he is doing.

He had a 45zx or 48zx in the shop today he was working on. Didn't even know they made them that big. Freaken nice boat.

[mrfixxall]

Valley Motorsports hooked it up to a propshaft dyno. The motor threw no codes. He did the compression test hot. I have all the cylinder readings out in the truck I'll post them later. Next comes leakdown test. He would have done them if I had asked but the main reason I took it there was to get it scanned. Didn't want to spend anymore money than I had to at the shop. The guy appears to know what he is doing.

He had a 45zx or 48zx in the shop today he was working on. Didn't even know they made them that big. Freaken nice boat.


CJ, see if you can turn your distributor, ive had a few in the shop that wouldnt rev and the timing was off because the hopd down was loose... ck your timing,if its not loose and its off then suspect your timing chain..

[CJmike]

Timing was checked. Fuel pressure was checked. Codes were checked.
Compression test was done hot. It appears I left the numbers sitting on the counter. I have the work order but looks like I forget the worksheet with the numbers on it.:bonk:

[CJmike]

1-120
2-120
3-115
4-100
5-120
6-115
7-120
8-105

[mrfixxall]

When running at idle does the engine rev (snappy) or is it sluggish?

[CJmike]

Sluggish. Performance is down across the board it seems.

[MOP]

Do one comp check hot followed by another with a small shot of oil in the cylinders, if it jumps up it is rings if it stays the same it is valves.

[CJmike]

Did the leak down test on Saturday. The rings are gone. Don't have the numbers handy but the hole with low compression was down around 24% the highest cylnder was around 80 with most in the 55-60 range.

Going to run it the way it is and hope it makes it until fall. Seems to run okay just down on power. Then it looks like it is time to pull it and build something new.

So now its time to start thinking about what the new combination will be.....

[BigGrizzly]

Seems like it started with the water pump failure, so as previously someone though about valves etc. Which could be the caused. This was common on 454 motor homes in the early 1980s, one over heat and unit loses power.

[mjw930]

Did the leak down test on Saturday. The rings are gone. Don't have the numbers handy but the hole with low compression was down around 24% the highest cylnder was around 80 with most in the 55-60 range.

Going to run it the way it is and hope it makes it until fall. Seems to run okay just down on power. Then it looks like it is time to pull it and build something new.

So now its time to start thinking about what the new combination will be.....

If it's a cash thing then I understand but I wouldn't wait if you can afford it now. There's no reason a shop can't R&R the motor in 2 weeks, unless it's a one man operation that puts larger jobs in front of you.

That gives you the rest of the summer and also could prevent a catastrophic failure that will cost you a lot more later on.

[CJmike]

Cash thing. Wife is currently seeking new employment. Besides doing it over the winter allows me more time to be creative with the rebuild. If I did it now it would come out and go back in much the same as it came out. This winter gives me options(454:502:540; maybe really big) I would like to buy some time so that the finances can get caught up and I can research what I want to do.

[BUIZILLA]

Bon Ami is your friend... :wink: :crossfing: :cool:

[mjw930]

Cash thing. Wife is currently seeking new employment. Besides doing it over the winter allows me more time to be creative with the rebuild. If I did it now it would come out and go back in much the same as it came out. This winter gives me options(454:502:540; maybe really big) I would like to buy some time so that the finances can get caught up and I can research what I want to do.

I understand completely. Although my motor is fine with plenty of power and easily another 400 or more hours left in it I'm fighting the urge to pull it out and let my engine guy at it. First I thought, well, I'll just ditch the peanut heads and do some nice edelbrock marine heads, cam, intake and a carb. Then I figure, hell, if I already have it out I should put in a decent bottom end with some new, forged 30 over pistons, nice rods and a forged crank. Before you know it I'm $7K into a motor that's running perfect today and now I need to do an exhaust and hey, I suppose external steering would be in order too :bonk:

I'm just going to run it for a while and be happy with the dead nuts reliable 330hp and 63 mph top end and lock that $15K into a nice 18 month CD so I can't touch it :wink:

[The Hedgehog]

I am sorry that happened to you. I could tell from talking to you and seeing your jeep videos that it was only a matter of time before some mods came. I figured that would happed this fall out of the need for speed not this summer from other issues.

If anyone has seen Mike's jeep videos, they would be afraid about what he might do with a boat!

That hull is a waver crusher supreme and loves power.

[mrfixxall]

Did the leak down test on Saturday. The rings are gone. Don't have the numbers handy but the hole with low compression was down around 24% the highest cylnder was around 80 with most in the 55-60 range.

Going to run it the way it is and hope it makes it until fall. Seems to run okay just down on power. Then it looks like it is time to pull it and build something new.

So now its time to start thinking about what the new combination will be.....


ok sluggish! AGAIN advance timing see if it gets snappy,if it does then Check or replace the timing chain..ShI$%#$ i use to run my stock cars at 7k at 230deg by the end of a race and it never went below 200 psi per cylinder. if you jumped a tooth on your timing chain you will get low cylinder numbers..its at leaste worth checking..

[MOP]

Bon Ami is your friend... :wink: :crossfing: :cool:

Ah Oh wise one I see you know a few resip engine guys, An old uncle of mine was on Guam he said all new resips got the treatment so the were combat ready it was SOP during WWII. Amazing what a table spoon sprinkled in will do!
Another thing to try is Merc carbon buster, how many times have you pulled one apart to find the rings carbon stuck but other wise acceptable. We used the OMC version on all our seasonal carbon/tune ups on our OB's many times there would be a decent jump in compression.

[RedDog]

Ah Oh wise one I see you know a few resip engine guys, An old uncle of mine was on Guam he said all new resips got the treatment so the were combat ready it was SOP during WWII. Amazing what a table spoon sprinkled in will do!
Another thing to try is Merc carbon buster, how many times have you pulled one apart to find the rings carbon stuck but other wise acceptable. We used the OMC version on all our seasonal carbon/tune ups on our OB's many times there would be a decent jump in compression.

Bon Ami sprinkled in the gas? in the oil? what are you suggesting and why?

[MOP]

Bon Ami sprinkled in the gas? in the oil? what are you suggesting and why?

Wind up the new engine and sprinkle in through the carb to break the rings in quickly, talk to any WWII crew chief they know the deal. When it was first told to me I thought my uncle was snowing me a bit! But later found out it was good for rings and getting rid of carbon deposits! Came under the category of live & learn, Goggle it I bet there is a ton of info on it.

Phil

[CJmike]

So I am suppose to get some of this Bon Ami, get the motor up to speed, and toss a tablespoon into the throttle body?

Just don't know about that one.....

[CJmike]

http://www.bonami.com/uses/fiberglass_boats.html

Says I can clean the boat with it.

[CJmike]

Dear Tom and Ray:

Have you ever heard of a "Bon Ami ring job"? I have an oil- and gas-guzzling 1984 Dodge Van with a 318 V8. I had a compression test done which revealed two or three cylinders with compression below 100. An old-timer friend of mine suggests using Bon Ami. He says it's an "old-time used-car-lot trick." He told me to take a shot glass full of Bon Ami (it has to be this brand of scouring powder because it doesn't scratch) and slowly pour it into the carburetor while the engine is running. My friend, Old Gene, explains: "The Bon Ami will dry up the oil in the cylinders for a few strokes, thereby causing the rings to burnish and reseat themselves." Gene claims I will see higher compression, more power and less oil burning for about the next 10,000 miles. Have you guys heard of this and will it work, or is it an urban legend? -Steve
Ray: Heard of it? We practically invented the Bon Ami ring job, Steve! When my http://www.cartalk.com/common/images/bluecar.gif brother was just starting to work at the garage, I gave him a nice easy job one day. I said to him ,"Go over there and clean out that carburetor." Next thing I knew, he was trying to save time by pouring Bon Ami down the throat.
Tom: I don't know if the customer's car ran any better, but I guarantee you he had the shiniest carburetor in town!
Ray: We'd have to classify the "Bon Ami ring job," as mostly a myth, Steve. It's one of those things that you try when you have absolutely nothing else left to lose. Like letting my brother work on your car. When the engine is junk anyway, why not pour a shot of Bon Ami in there, right? Heck, why not squeeze some of Old Gene's Dentu-Creme into each cylinder? It can't make things any worse, can it?
Tom: Well, it can, actually. Drying up the oil is just about the worst thing you can do to an engine. In fact, engine manufacturers go to great lengths to make sure you never run the cylinders without oil. Why? Because they know it ruins the engine.
Ray: In theory, the Bon Ami trick sounds good (this is the key to all lasting urban legends). You "rough up" the rings and get them to reseat themselves, forming a new, tighter seal. But in reality I wouldn't count on it. More likely, you'll rough up the rings and they'll stay roughed up.
Tom: And you don't even know if bad rings are your problem, Steve. Your lousy compression may be caused by bad valves. And we know for a fact that Bon Ami won't do anything for your valves (except, or course, remove the soap scum).
Ray: If you eventually determine that your rings are bad (by doing a "wet compression test"), and if you're going to rebuild the engine or junk the van soon anyway, then sure, go ahead and try the Bon Ami. Just don't be surprised if you get 10 more good miles instead of 10,000. Tom: And don't forget to put the Bon Ami back under the kitchen sink, so it's there next time your wife goes to look for it. Otherwise, you might find yourself in the embarrassing situation of having to confess to her exactly how you ruined the family car.

[BUIZILLA]

if you believe a thing that Ray and Tom say...

sell your boat




I spent a few years as an aircraft mechanic, then on to jet's as a lead nacelle tech....

engines on long term propane really benefit from it..

Bon Ami works...

you have absolutely nothing to lose at this point right?

[MOP]

There would be a few hundred American fighter planes downed in the Pacific if it were not for Bon Ami! You young ones need to listen up a little more! Non believers like I said Google Bon Ami that should close your yaps!!!!!!!!!

[BigGrizzly]

I was going to stay out of the Bon ami thing but Ray is an a$$ and wears a plaid used car salesman jacket. I too have used in a pinch. and I have cleaned the outside of carbs with it and some float bowls too. Poor little tooth brush. What MOP said is true. Weather it will work for you, just try it. At this point you can't loose. I am surprised that the engine even runs with those numbers.

[CJmike]

Motor made the summer. Had the last run yesterday. Pull the motor this Friday. Then take it apart and see what happened.

[mrfixxall]

Motor made the summer. Had the last run yesterday. Pull the motor this Friday. Then take it apart and see what happened.

I had 1 acting up a few weeks ago! then it finally died,it was dropping cylinders at idel when i got warm..I would flip the switch to the captains call and hold it and it would run fine..it turned out to be the pick up coil in the distributor..

[SilverBack]

I found this ad on boat freaks. I thought that you may be interested.

http://forums.boatfreaks.org/showthread.php?t=9743

[CJmike]

Hopefully my block is still good.

[CJmike]

2 cylinders had excessive ring gap that was resulting in a ton of blowby.
1 cylinder had excessive ring gap and had some blowby.

Heads looked good.
Block is currently bored .030 so it still has a few bores left in it.
Crank and rods look good. Only one rod had gotten to copper on the bearings
Block defiantly showed signs of the overheating.

[cutwater]

2 cylinders had excessive ring gap that was resulting in a ton of blowby.
1 cylinder had excessive ring gap and had some blowby.

Heads looked good.
Block is currently bored .030 so it still has a few bores left in it.
Crank and rods look good. Only one rod had gotten to copper on the bearings
Block defiantly showed signs of the overheating.

So how long were you running hot? 180* is high, but not unheard of. With a 160* Tstat you may see spikes close to 180*, but not for extended periods of time.

[CJmike]

Not long but unfortantly it was when the block was dry. First time out after winterrizing it and the system was empty. Seawater pump had died and dip**** new boat owner(me) didn't notice the problem when leaving the dock. Went out 150 yards at most before it shutdown. Expensive lesson learned. Check to see if water is coming out tailpipes after firing boat.

Also boat won't go out in the water dry again. I bought ear muffs for the drive so I can run it in the yard and check things out before getting on the water. The things you learn when you first get into a new sport.

[cutwater]

Not long but unfortantly it was when the block was dry. First time out after winterrizing it and the system was empty. Seawater pump had died and dip**** new boat owner(me) didn't notice the problem when leaving the dock. Went out 150 yards at most before it shutdown. Expensive lesson learned. Check to see if water is coming out tailpipes after firing boat.

Also boat won't go out in the water dry again. I bought ear muffs for the drive so I can run it in the yard and check things out before getting on the water. The things you learn when you first get into a new sport.

I've had my share of *doh!* moments... :wink:

[BUIZILLA]

I don't think you've found 1000 rpm loss worth of issues..

[The Hedgehog]

3 weak cylinders on a 454 in a heavy boat with 2 very weak. I am going to disagree, I think that you have found your rpm.

So what is it? A little boring, new rotating assembly, heads, cam, exhaust then sit tight for the blower?

That will really wake it up. Then add boost and you will be running with the twins, easy.

[CJmike]

Lots of thoughts little deciding

Go between a simple rebuild with a cam upgrade
to a stroker with the current block
to a 502 using a new block and the stock internals
or if Santa was really good this year all new stroked with new block.
But Santa said times are tough and not expect much this year.:boggled:

[TREYSTJOHN]

Before deciding on your block, I would highly recommend a sonic test to determine if the block cylinder walls will be thick enough once you go to .060. More than 50% of the time, we have found thickness to be unaceptable for raw water marine use on 454's(you want no less than .115"-.125" minimal thickness after final hone). We typically use Dart blocks which spec to .250 or greater after final. I would also have crank fluxed to make sure corners are not cracked. A couple hundred dollars spent to determine the condition of you existing parts will allow you to make some decisions going forward and prevent future ooooops if they are used in a marine rebuild when they should have been taken to the dump or turned into a low rpm street rod motor.

[The Hedgehog]

I am glad you made it through the summer. If you do the rebuild I would think hard about using a stroker assy. That would mitigate any problems with the crank and you can do some pretty good stuff without spending a fortune. You can even get a pretty good bit out of those heads if you want by punching them out, using good valves and a good valve job.

[mrfixxall]

I am glad you made it through the summer. If you do the rebuild I would think hard about using a stroker assy. That would mitigate any problems with the crank and you can do some pretty good stuff without spending a fortune. You can even get a pretty good bit out of those heads if you want by punching them out, using good valves and a good valve job.


Yeppers!:wink: 4.250 crank,no maching required,6.385 h beam rod,nice set of 14cc srp pistons and a isky I.553 E.578 duration at .050 I 228 deg E 238 deg on a 114 lobe center.and have 2.25 intake valves and some pocket porting on your heads will put you between 525 to 550 hp.

oops i ment 18 cc pistons :)

[The Hedgehog]

Yeppers!:wink: 4.250 crank,no maching required,6.385 h beam rod,nice set of 14cc srp pistons and a isky I.553 E.578 duration at .050 I 228 deg E 238 deg on a 114 lobe center.and have 2.25 intake valves and some pocket porting on your heads will put you between 525 to 550 hp.

Word!!!:kingme:

[SilverBack]

I would go with the 4.25 crank no matter what. This is the right time to do it and it does make a difference!!!

[CJmike]

Bores also checked out over spec. .008 over.
Frank says max marine is .005

Going to have to go .060 to rectify.

[MOP]

So how long were you running hot? 180* is high, but not unheard of. With a 160* Tstat you may see spikes close to 180*, but not for extended periods of time.

Curious why you think 180 is high, I run closed cooling with a 180 Tstat. All the new road engines run higher then that. When I raced Ford 60's we would see low 2's if the pace car stayed out for an extra lap, had to be moving along to get enough breeze through the radiators had no fans.

[f_inscreenname]

No matter what motor, Ford, Chrysler, Chevy I always run a 140 to 160 stat and running the motor hard would take it up to 180. Just the nature of a raw water motor to me.

[CJmike]

I don't think 180 is hot. If my race motor ever ran that cool I would be exstatic. Thats would the guage said but since there was any coolant in at the time since the seawater pump had died it wasn't reading correctly. The motor I would say was much hotter.

On a side not I had heard you should always use forged pistons in a marine motor. Yet this motor was a Merc remain according to the stickers and had hypereutectic pistons in it. Does that seem right?