What is Engine Backfire?
As is implied by the term “combustion engine,” a small engine creates and contains a series of small explosions within its combustion chamber. Sometimes, these explosions can occur outside of this chamber, such as in the engine intake valves, or in the exhaust system connected to the engine. This can occur if fuel begins burning inside the engine before the intake valves have fully closed, but it can also occur if fuel finds its way into the exhaust system and collects in small pockets. When these explosions occur, a loud bang will typically be heard, and it may be possible to see a brief but intense flame emanate from the exhaust pipe. Causes Related to Fuel Systems Low fuel pressure can cause engine backfire through the exhaust system. When fuel pressure is low, the ratio of air to fuel inside the combustion chamber becomes too high. Often, this will under-power the engine for a few seconds or more, during which time some of the fuel in the chamber may not become ignited. This fuel b
