Originally Posted by YardApeMike
How would you notice a backfire with that air cleaner case? I heard a suggestion that it comes from repeatably turning off the engine while at full throttle. We are now looking at these daily.
Don't know the B&S procedure but my Kawasaki manual says to start/stop at 1/3 throttle. Shutting off ignition at full throttle; it will continue to pull fuel/air mixture into the cylinder where a piece of hot carbon or a hot spot can ignite the mixture and if the intake valve is open when mixture ignites, will blow back through carburetor. This may not be a complete burn of fuel in the cylinder but create enough heat to melt that filter media. That looks like some type of nylon, is that right?