85hp acceleration

[gussbuster]

Hi, Im new to the forum and i have a 1989 85hp. When Im on the lake and accelerate from a stop, the engine will stutter for a few seconds before finally opening up to wide open. I have new plugs installed and wonder where i should look first. Any ideas would save me a lot of diag. Thanks!

 

[roscoe]

Re: 85hp acceleration

Welcome to iboats gussbuster.

A 2 second stutter on initial acceleration is good for a 2 cycle motor.
It is a lag time for the fuel and timing advance to get synced up.

Stutter and acceleration- good, probably have the carbs running rich enough to provide adequate lubrication.

No stutter at all, carbs are too lean, motor not getting adequate fuel and lubrication.

A stumble and killed motor- carbs are way too lean, engine will die a grueling death.

If the stutter/hesitation happens further into the power band, you may have a problem, likely fuel related.

If the stutter lasts a long time and engine can't plane the boat, you need to look further into the problem.

 

[gussbuster]

Re: 85hp acceleration

Thanks roscoe!!

I didnt know a few second lag is normal, however, mine is more of a 5-8 second stutter...almost like its bogging a bit. Fuel is something I will definately have to take a look at. Has anyone had problems with fuel filter/diaphram? Could this be the culprit??

 

[roscoe]

Re: 85hp acceleration

If the fuel pump diaphram was the culprit, the problem would get worse at full throttle.

Chances are you need to rebuild and adjust the carbs.