Ok, this motor sat up for 4 years before I got it, and I bought it from the original owner.

I drained the gas tank as good as I could (leaving maybe 1/4 gallon of old fuel).

Changed plugs, rebuilt and cleaned all three carbs, and changed impeller.

Added Stabil (Marine mix), and Seafom, then put 5 gallons of 93 octane fuel.

Started the engine in the water (fired up within 1 second of turning the key.

Does not want to idle, have to give it mild throttle to keep it running (1100 RPM).

But here is the weird part...about every 5 seconds, it�s like someone hits the engine with a sledge hammer.

The engine will be idling and then *WHACK*, and it even makes the steering wheel jerk to the side.

Runs fine at anything above 1100 RPM, and actually runs great at full throttle.

Stays at about 6500 RPM at WOT.

Just can�t fogure out why it won�t idle below 1100 RPM (dies), or what that *BANG- WHACK* is every 5 or so seconds when at idle below 1200.

Any help would be appreciated.

Idle circuits clogged up in the carbs. That whack is a lean cough.

Carb job time, hopefully last guy didn't mess with adjustments screw.

I rebuilt the carbs before I ever tried to start it...I didn�t mess with any of the adjustments...just took them off and rebuilt them then put them back on.

So they need adjustment?

1/4 turn on the mixture screw and all is well...thanks guys.