mercruiser 120,1986, hesitates on acceleration, sylvan 20 offshore

[chevykubala]

the engine starts and runs fine, we put in new gas this year(non ethanol) but the engine hesitates when u put on the gas, it will go up to full speed if it gets coaxed by slowly pushing up the throttle and runs fine at full throttle(3000 rpm). We just bought this boat this winter it has been sitting out since 2004, we emptied out both gas tanks and changed the gas filter, I think it is a carb problem but am not sure and am open to ideas, I cannot seem to find a water seperator to change.

 

[cedgo]

Re: mercruiser 120,1986, hesitates on acceleration, sylvan 20 offshore

Hello, sounds like a related problem I have been having. Better advice here than mine, but you should be running around 4500 RPM.

 

[Bondo]

Re: mercruiser 120,1986, hesitates on acceleration, sylvan 20 offshore

the engine starts and runs fine, we put in new gas this year(non ethanol) but the engine hesitates when u put on the gas, it will go up to full speed if it gets coaxed by slowly pushing up the throttle and runs fine at full throttle(3000 rpm). We just bought this boat this winter it has been sitting out since 2004, we emptied out both gas tanks and changed the gas filter, I think it is a carb problem but am not sure and am open to ideas, I cannot seem to find a water seperator to change.

Ayuh,.... Welcome Aboard,... It didn't come with a canister filter, but you can add 1,...

There is a filter in the fuel pump, 'n another in the carb's inlet,...

I agree, ya got a Carb problem,...
I'd do a Rebuild kit, 'n include an accelerator pump kit too,...

The accelerator pump is yer get-up, 'n Go problem,...

 

[tjordan]

Re: mercruiser 120,1986, hesitates on acceleration, sylvan 20 offshore

Had the same hesitation powering up from idle (3.0 L). Pulled the top of the carb and replaced the accelerator pump. Hesitation solved. Just remember how all the linkages go back together.