PDA

View Full Version : New Engine update



Jamesbon
11-06-2000, 09:33 AM
Okay, another weekend of mostly successful testing has passed. I put about 4 more hours on the 388 with no apparent problems accept for that pesky oil leak between the timing chain cover and oil pan, and I noticed what I suspect is possibly fuel starvation at full throttle. Only about twice did the engine only pull to 47/4800 rpm's when at full throttle. The other 8-10 full throttle blasts were all between 5000 and 5200 rpm. She didn't pop or backfire or anything, just wouldn't fully rev up. I suspect my fuel pump or 3/8 OD diameter lines can't keep up with the demand for fuel at full throttle?? I may put the 750 Holley on for the next trial and see what happens before I go upsizing the fuel pump and associated lines.

This week I have to pull the engine a few feet above her nest and remove the oil pan and install new gaskets and sealer, I can't wait! http://www.donzi.net/ubb/rolleyes.gif

I adjusted the torque steer fin for a big difference in steering torque. It's fine up to about 3800 rpm, then she starts pulling hard. I guess I'll keep turning the fin till the torque is fully counteracted?? I really need an external steering set up, this cable stuff is ridiculous! (Or ASD #6 http://www.donzi.net/ubb/biggrin.gif )

If I consistently pull 5000-5200 rpm's with a 15 X 24, would it make sense to try a 25 or 26 pitch prop? I wouldn't mind the slightly higher cruising speed that would offer.

Also, both of my Bennet trim tabs work, however, the one on the port side retracts within 30 seconds of being fully extended when underway. I assume, it's got a bad seal or something within the hydraulic ram itself? Are these rebuildable?



[This message has been edited by Jamesbon (edited 11-06-2000).]

PaulO
11-06-2000, 10:48 AM
If you don't mind, I will tag along on your post. I finally got the 383 back together and in the water this past Saturday. Chris (CDMA) joined me for a great ride. Sucked some seaweed initially that brought the temp up and scared the *&&%^(%$ out of me! After clearing that, the boat ran flawlessy for a couple of hours straight. Several prolonged full throttle blasts showed no sign of my previous full throttle only overheating problem. Makes me wonder if I had a head gasket problem from the get-go. Beat some hydrostream that couldn't keep up with us in the chop, was pulling on some outboard superboat/activator until we got tired of that and got the old girl out into the ocean for some swell-jumping!! Finally, a great day with this new motor.
Jamesbon - my 383 with the Holley 750 seems to be okay with the 3/8 fuel lines. As for your oil leak - my last motor leaked in the same place and I had to pull it too.
Now, gotta find an SS this winter or figure out how to shorten a regulat Alpha!
PaulO

CDMA
11-06-2000, 11:15 AM
What a ride it was. I was amazed the difference in the Alpha set up as upposed to my Volvo. The boat rides a lot higher out of the water. The trim makes such a difference. Maybe next winter I will spend some time in the machine shop and build 270/280 retrofit kits for the Vovlo.

Anyone out there ever "shorten" a drive like Paul O refered to. Is it really a viable option.

Chris


Chris

woodsy32
11-06-2000, 12:09 PM
Chris,

IMCO makes a shortened Bravo lower unit, but it is huge $$$, somewhere along the lines of about $6000. If you give them a lower unit they will rework it for about $4000. But you guys with Alpha setups are pretty much out of luck. If you can find an Alpha SS, I think that would would work, but those are rare, and the owners usually want serious $$$. I would consider either raising the engine to gain a shorter X-dim, or switching to a bravo setup so you can run more HP. Just my $.02

Dave

GeneD
11-06-2000, 01:36 PM
Interesting you think the fuel is starving.
I just read a little blurb on the Merc site about using non-hardened fuel pump rods on roller cam motors. Apparently they wear out rapidly according to Merc.
I'm wondering if my rod is now shortened and not pumping in enough fuel!
I haven't noticed any metal in the oil though. Could it be that the old rod is shorter than the new rod? Anyone got a clue?
Great to hear both of you guys are up and running good.
Oil leaks suck.
Yeah, Chris, when I had my Alpha One, I loved the way the boat trimmed out. The SS does not get bow lift like the one One's do. And you can't beat power steering to counteract that torque steer thing.
Way to go boys!

------------------
GeneD
007
Melbourne, Florida

GEOO
11-06-2000, 04:50 PM
Nate,
Glad to hear you're up and running strong. I'm baffled on the lost rpm's; good luck!!

PaulO,
Sounds like you're up and running strong. Congrats!! I'm jealous you and Chris made it out last weekend. I better have mine back together in the early winter so it will be all ready for the spring.

I'll keep my eye's out for an SS drive or an ASD6.

Chris, So you like trim!!! I recall seeing a Merc. trim kit on a Volvo in one of the posts. GEOO

Scott Pearson
11-06-2000, 05:38 PM
You know...I bet I can short'n an Alpha. I will look for a donor drive and give it a try. Could be interesting! Gotta get my boat done first.

(NJ)Scott

GEOO
11-06-2000, 05:46 PM
HUMM!!! Sounds like a fun project. I bet you could sell half a dozen on these site alone. GEOO