why do engines backfire?

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  • why do engines backfire?


Answer #1 | 22/12 2013 12:50
This condition it happen in the engine ,when crank shaft rotate opposite direction .In that case component in the head cylinder will operate opposite to and you will see fire coming out of exhaust. Reason it can be ring jammed -up cause of the cold . Turn off the engine and check the timing gear of the motor it may timing move from the original position .Re time the engine and start again. In cold condition engine even gas engine must get warm before start except engine that are design for the cold condition .
Answer #2 | 22/12 2013 13:33
Unburned fuel in the cylinder. Running to rich.
Answer #3 | 22/12 2013 16:02
There's rust/particles on the flywheel shorting out the spark..Timing..Or you need a new Plug,.. or you have the wrong plug..Or the choke is staying on....or you have a plugged (Paper) air filter.. On the smaller engines the timing is off because of a bent flywheel shaft key.. Or you have water in the Float bowl of the Carburetor. If it's an old.... points... Briggs,.. there's oil on the points contact..
Answer #4 | 22/12 2013 13:54
The back fire is caused by unburned gas getting into the exhaust manifold. You have fuel, air, compression and spark. That leaves the timing of all of the components. If the spark ignites the fuel at the correct time it will be consumed before the exhaust valve opens but if the spark is delayed too much the valve opens and raw gas goes into the exhaust manifold and is then ignited. I suggest you get a Service and maintenance manual for the engine and determine what could have happened to cause this. I suspect that the problem is the timing in the magneto has changed. This could be a bent key or the pick up is loose.

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