www.iFourWinns.com

its a horizon 240 volvo penta duoprop
engine 5.7 GSi with twin tbi
engine has developed a serious problem with lack of power
i guess it has a miss
this is what ive done:

changed:
plugs, wires, cap, rotor, fuel filters

compression test is 180 psi in each cylinder

ran the motor on a fresh can of gas so water in fuel not issue

all valve springs, rocker arms, pushrods seem to be perfect
im out of ideas HELP! (please)

Have you checked the exhaust manifolds? They could be partially clogged.

yes, they were pretty clean boat only has about 150 hours in freshwater

If you run it without the flame arrester, is the fuel atomizing nicely as it comes out of the injectors in the throttle body, or is one or both of the injectors "dribbling". "Beyondtheblue" had that issue with the injectors on his engine a few years ago.

Graham

both throttle bodies have nice cones identica to each other

On my first boat, I did a tune up, and crossed one the wires to the wrong plug. I hope it is that simple for you, but go over your work. What about timing, do you have a timing gun?

You could invest into a computer diagnostic tool?? Is the cost worth it?

No.

_________________
One of 4 Previous (Sold) Boats:
2000 Four Winns 268 Vista

Current Boat: 2004 Chaparral 235 ssi cuddy

Thats for dukeschuff to answer.

But I can answer if I like. Because I have went down this road before.

I suspect he will agree, unless he plans on working on engines for a living, the cost outweighs the benefits
for the limited use most boaters would get out of the tool.

I had a very similar problem as he is having , with our 268. Did everything he has already done. Even put the
engine on a laptop with Volvo diagnostic software. None of it diagnosed or cured the problem.

_________________
One of 4 Previous (Sold) Boats:
2000 Four Winns 268 Vista

Current Boat: 2004 Chaparral 235 ssi cuddy

i would bring it to repair shop before i bought a diagnostic tool i guess i am at that point

That's exactly what I did.

_________________
One of 4 Previous (Sold) Boats:
2000 Four Winns 268 Vista

Current Boat: 2004 Chaparral 235 ssi cuddy

well anyone else got any ideas?

So the cost was not worth it for the tool! I did not think so.

Captain, you said "I had a very similar problem as he is having" Maybe dukeschuff could try what the mechince found wrong with your engine. Just a thought?

Was thinking the same thing, Cap'n. What did it turn out to be?

_________________
Paul
2007 Four Winns Horizon 220
Mercruiser 350 Mag MPI w/ Bravo III Drive
2004 Ford Explorer Limited (V8-AWD)
Pomme de Terre Lake (Southwest Missouri)

I have recently been fighting similar with my merc. Went down the road of Rinda Diagnostic tool. I don't think it helped this time, but niether has the shop, or Merc for that matter. Just yesterday I changed the cap and rotor, and found one wire not making well. Fingers crossed it's that simple. Ran through the same testing as you did otherwise... even replaced fuel pump.

As far as the "tool", I think it's a worthwile investment if you buy it, and record some baseline data when everything is running right. This can help imensely. I didn't do that!

_________________
Walt B
"Debt-Charged"
Black '07 H210SS
6.2L Bravo One turning a 21P HIFive
Wakeboard Tower with Perfect Pass Stargazer version
Missouri River; Kansas City, Mo.