1973 20' SF - Engine Trouble?

[gofastsandman]

Compression should be measured w/ motor cold, not hot, and all plugs out for 2 strokes.
Just a thought, how are your threads in the head? Someone may have galled them or semi - stripped them. Can you feel any blow by the plug while someone else cranks the motor?


How much power tune did you use and how long was the soak?
Was the motor tilted all the way up and the trailer tongue down as low as possible? Do you have a hill where you can move it to and chock the tires . Get the motor as horizontal as possible. I`d try again. Carbon is strong enough to blow rings and landings and I`d give it some time again. Get a strong small flashlight and check the cylinder for scoring at night while rotating the flywheel so the piston hits bottom dead center and leave it there for the decarb. All wires off and plugs out please.
GFS