What causes engine backfire out of the carburetor or muffler?
“Backfiring” is a condition described as a loud bang, poof, explosion, etc. when idling the engine down, or after the engine has been shut off. (Note: “Afterfire” and/or “Backfire” will not harm the engine at all!) “Afterfire” occurs after the engine has been shut off. Some possible causes include: • Shutting off the engine at high RPM. This can result in some fuel being pumped through the engine and into the hot muffler, causing that fuel to ignite. • Gasoline that contains alcohol has a tendency to ignite easier, plus cause the engine to run slightly hotter. This, combined with a hot muffler, can cause afterfire. • The type of muffler that has been installed by the equipment manufacturer may cause afterfire. • Carburetor adjustments may not be properly set to insure correct engine performance. • If anti-afterfire solenoid is installed it may not be working properly. Some possible cures include: • Idling the engine down to the proper idle speed for 15-30 seconds. This would allow the
