Merc 78 140HP Problems

[Chunks]

I have a 140hp Merc that starts fine and idles but after a minute or so at idle it will slowly drop in speed then stall. I have noticed fuel dripping from the bottom throttle shaft after it stops. I then have to use the warmup lever to get it going again. The other problem is that when you stop the motor say for a few minutes or so after you have towed a skier etc i have to use the lever again and as soon as you drop it into gear and try to throttle it will die. The only way to get it to go is to slowly put the throttle on until it picks up speed.
I had a mechanic adjust the ide mixture but dont think it is right still.
Hope you can help.

 

[j_martin]

Re: Merc 78 140HP Problems

What happens if you pump the primer bulb as it's starting to stall?

 

[Chris1956]

Re: Merc 78 140HP Problems

Chunks, It sounds like the bottom carb has a bad float setting or a bad float needle. You might remove the carb cover and inspect the needle and seat, as well as the float levers. The float should have a small spring on top of it, and if it is the foam kind, replace it. If the inlet needle is the brass with rubber center and the needle is plastic, replace that as well. They have both been superseeded, with good reason.