Backfire Tecumseh Generator

To maybe convert your Flamethrower back to a generator, Make sure the fuel line is a good quality thick rubber material (like OEM )since it passes through the engine,HEAT is a issue, if it has been modified to steel, or it's thin rubber, it will overheat the fuel on its way to the carb and cause backfires after the engine warms up , ( vaporizing gas and pressure bypassing the jets flooding the engine) I use 1/4 inch Goodyear sold at Autozone , one of very few name brand quality parts you can get there. The other possible cause is carbon deposits built up on the leading edge of the valve not allowing the valve to close all the way, just clean the valve, it is caused by too lean or rich carb setting or clogged jets, if it is a newer style carb with a pink main jet then debris in this area will always cause backfire, check and make sure the old tiny O-ring on this jet is not still in the bottom of the shaft, people forget to pull them out all the time or give up trying to pull them out, I use a paper clip and bend the end 1/8 of a inch @ 90 degrees to fish hook it out of there, CLEAN THE SHAFT with carb cleaner and a Q-tip.... A Tecumseh engine will always backfire if the carb or airflow is not perfect and sealed tight !!!!!! it looks simple to rebuild the carb but you must take your time and look close, clean it very well, make sure the jet is SEATED properly and all tiny holes are clean, use guitar string not torch head cleaners as they will enlarge the holes and make your carb run rich.

I just had this problem on a tecumseh 12hp engine on a snowblower. The problem turned out to be a rubber hose that was off of the carberator. It was cracked and split. It was backfiring about every 5 - 10 seconds. All I did was snip the hose and put it back on and it ran fine. It was not the fuel line, I think it was a line for the primer. At any rate that would be something to check.