So the last time I took my boat out, it did not want do idle well and it would shut off. Its a 35 with IM heads and single mikuni. It would also sputter when going from an idle to WOT. A few days later when I cranked it up it would rev up on its own to about 2200rpms, then drop back down and shut itself off. When I hit the throttle, the response is good but it doesnt drop back down in rpm's like it should, it slowly drops, then may go back up. I figured it was bad gas or a gummed up carb. So I took the carb off and cleaned out the bowl with carb cleaner and sprayed what I could from the outside. I did not take the carb completely apart. I also replaced the gas and added seafoam. After this it is still doing this. I have also tried turning the air mixture screw all the way in to 3 turns out with no help. So any help or advice would be appreciated.

it sounds like you have a vacuum leak somewhere

Spray carb cleaner around the head/intake, intake/adapter, adapter/carb. See if it changes the way the motor runs. If it does, you have an intake leak. Those can all be symptoms of that.

Turning the idle mixture screw out is just letting more air in.

[quote="cb5331"]Spray carb cleaner around the head/intake, intake/adapter, adapter/carb. See if it changes the way the motor runs. If it does, you have an intake leak. Those can all be symptoms of that.[/quot


it will let you know real quick

That's fine. People that say theirs run best under 1 turn out have too small of a pilot jet. Per the mikuni tuning manual.

Did you make any adjustments to anything before it started acting up?