by Ed
(groton, CT)
Starts fine and runs at idle smoothly until it warms up and rpms drop a bit. Then starts hunting, i.e., momentarily goes up 100 rpms then down 100 rpms. Under load it continues to hunt until around 3500 rpms after that it smooths out and runs well at WOT around 5200 rpms.
Bypassed fuel tank and attached 6 gallon tank with unleaded ethanol free fuel. Ran Seafoam thru several times. Checked spark strength and inspected plugs - all ok.
Havent found source of problem.