Mercruiser 3.0 power loss

[Kwbruce]

I have a 1996 caravelle with a mercruiser 3.0 alpha one. I just recently experienced some major power loss. The engine idles rough and if I have more than 2 people on the boat I cannot get it to plane at full throttle. The RPMs won't get above 3500 and it just sounds sluggish. I removed the plugs when I got home and they all were blackened and still moist with fuel. Do I need a tune up or do I have a carb issue? Any help would be most appreciated.

 

[alldodge]

Howdy

Look down the throat of the carb with it running and see if you see fuel dripping. Then shut the motor off and see if fuel drips (it should not in either case). If it is dripping you need to rebuild/replace the carb.

If no dripping is found I would start with a compression test to determine if there are internal issues causing the excessive fuel usage.

 

[Rick Stephens]

I would bet that your carb needs a rebuild. I would bet more boat carburetors, after 6-8 years of on and off use, need a cleanup/rebuild than don't need a cleanup/rebuild. Nature of the beast. They sit a lot. Are used in a water environment. Get used hard and put away for months at a time with questionable fuel quality. Ethanol fuels break down and leave deposits in the carburetor. Old fuels break down and leave crud in the carburetor.

Take a look at fuel filters and separator and replace
Rebuild the carb

Go boating