Unstable rpm when trolling

[Bryan Gould]

I have a 9.9 4-stroke, runs and starts great but I have a hard time maintaining a constant trolling rpm. It iether climbs or drops after a bit of time. Any suggestions?

 

[hondadude]

Not sure which generation 9,9 that you have, but the typical causes of this kind of problem are...

Thermostat stuck open...and engine running too cold.
Partially clogged idle passage in carburetor
Improperly set idle mixture.
Poor compression
Valves out of adjustment.
Bad spark plug
Bad fuel and/or water in fuel.

There are a few things it could be.

Mike

 

[Bryan Gould]

Not sure which generation 9,9 that you have, but the typical causes of this kind of problem are...

Thermostat stuck open...and engine running too cold.
Partially clogged idle passage in carburetor
Improperly set idle mixture.
Poor compression
Valves out of adjustment.
Bad spark plug
Bad fuel and/or water in fuel.

There are a few things it could be.

Mike

Thanks I'll check some of those things out.