running 50:1 ashless lawnboy.....Not too heavy


What is backflow on the exhaust? never heard of that?


Its a 3W106 , the Pic is kinda cloudy but neither plug is cracked. Carb is unrestricted.........plus the motor runs fine at full, 1/2, idle until like the 5min mark. So its got something to do with the heat. is it heat on the plug, ignition box, rings, etc. looking for some educated help before I pack it up and send it in to be looked at.