If running it doesn't get it done, (it probably will), you don't have to do a disassembly complete to wash the engine in lacquer thinner. Just remove the backplate and carburetor maybe the head too and slosh the engine and carburetor around in a coffee can of lacquer thinner for a couple of minutes. Spin the engine over while in the lacquer thinner to help work the thinner in the ring grove. Drain and shake the thinner out of of the engine, lube it and you are ready to go.

If Pe is correct about that engine having a dykes ring then as he says it will never feel like it has much compression when being turned over by hand. Also if it is a dykes ring gummed up oil and/or carbon between the ring and the piston can turn that ring and maybe the piston and cylinder to junk in a hurry.

Denis