Re: would to much 2stroke make engine backfire
It would take an awful lot. If you mixed double or triple the amount, it would still run. Stale fuel would cause an otherwise well running motor to do that. You'd be able to smell it. When it goes bad, it smells nothing like what you pump at the station.<br /><br />You might just need to richen your idle mixture a bit. The idle mixture jet is near the top of the carb. It might need to be unscrewed 1/4 turn (give or take) to richen the mixture.<br /><br />I see somebody already addressed syncronization. At idle the throttle butterfly should be completely closed. There is a mark on the cam that rubs on the roller that opens the throttle. That mark should align with the middle of the roller when the throttle butterfly starts to open. (There's slop in the linkages, so it's not when the roller touches the cam that needs to be addressed, but when all that mechanism actually starts to open the butterfly.) Then the butterfly needs to be flat-open at full throttle.<br /><br />Is it starting at all? Check your sparkplug wires. If they're swapped, you'll get backfiring when you try to start it and it won't start or run. If that's the case, check that first.
