Force 120 at idle

[ForceFive]

Hi guys,

This year I've used the boat twice and both times when reducing the speed to idle the engine dies. Even launching and trying to back out form the dock it will die each and every time. Does anybody know it this is a fuel filter problem or something else.. I have four cylinders and two carbs both linked together of course It will start each time wubt when shifting to forward or reverse she dies. Out on the lake I've had to quickly shift into forward to get going and back to the dock.. Only at higher rpms will she keep going.

Thanks,
Dave

 

[Robert D]

Re: Force 120 at idle

Check the fuel mixture...sounds like it may be a little lean. Adjust it at an idle, in gear, and in the water. (Tied to the dock, or strapped onto the trailer and backed down the ramp both work well.)

Can also be a multitude of other items....old gas, gummed up carbs, old plugs, timing....adjusting the idle mixture is the least expensive to start with, but make sure you have fresh gas.

Generally, screw the mixture screw in until it lightly bottoms out. Don't force it down tight. Back out one turn, start the engine and adjust from there. In for lean, out for rich. Do this on a warmed up engine by the way. Once you find the spot it idles at best, I usually go out about 1/8th of a turn. Allow time between adjustments for things to stabilize.

Just a tiny amount the wrong way, like 1/16th of a turn.....can cause it to stall when going into gear. You might just try backing out the mixture screws a little and see if that cures the problem....

 

[ForceFive]

Re: Force 120 at idle

Thanks, Robert I'll try that. I do have a large conatiner that the lower unit will fit into and be completely submerged. I'll let you knwo what happens.

 

[foodfisher]

Re: Force 120 at idle

You probably answered your own question with the higher rpm's statement. At idle, in gear, in the water (not bucket or ears), rpms should be 750-800.

 

[afd21]

Re: Force 120 at idle

I was having this same problem and it tunred out my fuel/oil mix ratio was off. I cleaned out the carbs and got the correct mix ratio and it seemed to clear up for me.