I got a mercruiser in my truck and need help getting it to run good.

[billyrumbo]

I just put a 165hp mercruiser inline six in my truck, it runs great around town but as soon as I hop on the freeway or put my foot in the gas to climb a hill it cuts out and runs out of power. Im thinking it has to do with the distributor not having a vacume advance? If anybody is familiar with this problem I would greatly appreciate the feedback.

-bill

 

[Lyle29464]

Re: I got a mercruiser in my truck and need help getting it to run good.

should work fine. should not miss till it tops out in rpm. ( 4200) or so. I would look at the advance first then fuel flow.

 

[Bondo]

Re: I got a mercruiser in my truck and need help getting it to run good.

Ayuh,... Sounds more like a fuel delivery issue,...
Fuel fliters,..??
Carb,..??

 

[Don S]

Re: I got a mercruiser in my truck and need help getting it to run good.

Moving to Non boating tech topics.
Just like automotive engines not working properly in a boat, a marine engine doesn't work very well in a truck without the proper modifications. The ignition system is one of them.

 

[fossill]

Re: I got a mercruiser in my truck and need help getting it to run good.

I just put a 165hp mercruiser inline six in my truck, it runs great around town but as soon as I hop on the freeway or put my foot in the gas to climb a hill it cuts out and runs out of power. Im thinking it has to do with the distributor not having a vacume advance? If anybody is familiar with this problem I would greatly appreciate the feedback.

-bill

Vacuum advance is for fuel economy. Has nothing to do with power. At wide open throttle you got very lirtle vacuum.

 

[kd7isf]

Re: I got a mercruiser in my truck and need help getting it to run good.

Keep in mind that the power band in a marine engine is much narrower than in the typical road vehicle... Ignition timing and cam are different...

In your situation, though, you are having problems where a marine engine should be the best -- high load.
As said above, fuel delivery... Carb, fuel lines, fuel filter, fuel pump, FUEL VENT -- Is your truck's tank vented?
Take the gas cap off and try the same hill again -- most marine engines are designed to run with a vented tank -- a lot of cars and trucks are designed to run with a NON VENTED TANK -- this is a smog thing -- you can fix it by buying a vented gas cap for it...

Hope this helps

 

[marcoalza]

Re: I got a mercruiser in my truck and need help getting it to run good.

It would be interesting to see torque curve and power band graphs for these engines as I'm pretty sure they would differ from a similar road car engine.
This would typically make it run out of steam at higher revs.
If you cannot find a fault it may be inherant in the engine design.

When you say "cuts out" does it actually cut out or lose power?

 

[Solittle]

Re: I got a mercruiser in my truck and need help getting it to run good.

I'm guessin but I think marine engines have different cams than their automotive brothers.

 

[88wellcraft]

Re: I got a mercruiser in my truck and need help getting it to run good.

Kinda funny.....usually we're talking automotive engines for marine applications......

 

[Fireman431]

Re: I got a mercruiser in my truck and need help getting it to run good.

I wonder if it has something to do with the propeller dragging on the pavement...

 

[billyrumbo]

Re: I got a mercruiser in my truck and need help getting it to run good.

Thank you for the replies. I've narrowed it down to the carb. I tried the gas cap off idea, no go. Maybe the steel fuel line is gunked up, truck sat for years, but im pretty sure its a fuel delivery problem. I put a new fuel pump on it and it got better immediately but not totally better. Still seems starved for gas going up steep hills. Im going to try another another carburator, blowing out the steel line from the tank, then possibly a different distributor and if the problem persists, i'll be posting a Mercruiser 165hp six banger for 200 bucks on this cool site cause it probably belongs in a boat

Thanks again!

 

[billyrumbo]

Re: I got a mercruiser in my truck and need help getting it to run good.

it loses power, seems to want to totally die unless i back off the gas pedel and slow down to about 15mph. both i guess...