1988 mercury 100 hp - Starting and running issues

[domboat]

Hi, I have a mercury 100hp 88 outboard, i have some issues with the engine fluctuating rpm. I was thinking the gas line had air in it or a sticky carb. I added an additive to the gas and i think it worked because it seemed to run without fluctuating. The issue now (can be related) is that it won't always start or starts when the trim is up. Ok at higher RPM but dies when i throttle down or lower the trim. I wanted to add that it seems to smoke more and noticed some gass in the water when running. Is it a cylinder not working - carb or is it something else? Thanks

 

[quicktach]

Sounds like a carb issue for starters....because of the level starting condition and gas in the water.....I'd go after the carb servicing first.
What's engine serial number?

 

[domboat]

the serial number is OA738777 It can very well be i didn't use the boat last summer and it isn't used much. I'm having a difficult time finding a place that would service an old engine.

 

[domboat]

The boat started with no issues ran fair when parked but when I went out today with the boat it didn't want to go. The engine seemed to vibrate quite a bit and wouldn't get to the high rpm's. On occasion it would got back to it's normal self and then fall sluggish again.

 

[Masonmoore]

I agree with quicktach, its definitely a carb issue. It sounds like some sticky floats since it will only start with the trim up. As for the rpm problem, this is usually because of gummed up jets. Have you taken the carbs apart?