engine runs but dies

[Gatherusin]

1991 Starcraft with 3.0 mercruiser I/O. Since we’ve gotten into cooler weather up north, boat will start up ok and run but after about 5 min it will start to sputter. You can rev the engine and it’ll bounce back but then start to struggle again. It eventually will die. However, after restarting it, it seems to be ok and has no issue. I try and keep it running the first time, reving it as needed thinking once the engine is warm it will be ok, but it’s like it has to die at least once before it will finally just act normal. Thoughts?

 

[achris]

Full tune up/service (including compression test), possibly needs a carb rebuild too (strip and clean).

 

[Bt Doctur]

last complete tune up, fuel filter check/change,

 

[Bondo]

Ayuh,..... Welcome Aboard,.... I agree, sounds like it's runnin' outa gas as the choke opens, which probably means a restriction in the carb's idle circuit,....

 

[alldodge]

Agree fuel issue.
When changing the filters, don't forget the one in the carb

https://www.mercruiserparts.com/bam/subassembly/30914/1604/130

 

[crazy charlie]

I always start with something simple.I would replace the fuel/water seperator.Pour ir into an old mayonaise type jar and leave it for a while and see what it looks like in an hour or so.You may be shocked when the fuel seperates from the water.Charlie

 

[aimlow]

Sounds lean. Does the engine warm up properly,,,t'stat working? In cold weather, the intake manifold must be warm to keep the air/fuel charge atomized, otherwise fuel condenses out before getting to the cylinders.

Choke may be opening too early also.