This is not one of my minithings. I put a Predator 420 on my son's yard tractor because he hated pulling the rope on the 212. {Merry Christmas} We have to choke it to start it even when it is warm, and if we raise the throttle too fast when it's in gear, it stalls. Is there a carb kit or a jet kit for this engine? The Hemi that came off this tractor is going on a custom bent exhaust pipe framed rear engined dune blaster. Look for something in the build section. I will be bending pipe tomorrow. Please help me richen up this 420. Thanks. Dave