Engine was run low on oil and piston seized. Was able to free it up and it has 55psi comp cold and about 70 with a tablespoon or so of eng oil. I know nothing of the previous history on this engine. Engine is stubborn to crank and needs excessive choking. When it starts, will take full load,but when it idles, may idle a min or two before becoming erratic and then stopping. Carb has been thouroughly cleaned with welch plug and needle removed and all passages punched out, sprayed with carb cleaner and blown out with compressed air, Also new fuel pump membrane installed. Could this be a compression issue, or have I overlooked something on the carb. Plug changed also and Idle adjusted to 2200 with tach????????.PS evidence of some scoring on major thrust side of cylinder.