Office of Steam Forum for Model & Toy Steam Gas & Hot Air Engines

Rich, I had the exact same problems at first...zero compression and fuel spitting out the carb and tank. 

Ended up pulling the engine apart and though piston had two grooves for rings, only one ring was present and was set in the upper groove.  I removed the silicone ring from the upper groove and placed it in the lower groove, oiled it well and reassembled.  Now engine performs perfectly and has run several hours with this minor change and has plenty of compression.

Roger