Gravy
Platinum Member
Hey folks,
I haven't been around much for quite a while, but a recent thread reminded me of a problem I solved quite a few years ago: The dreaded backfire a few seconds after shutdown. Maybe somebody else already did this, but I'll go ahead anyway.
It occurred to me that turning off the ignition on a hot engine allows the engine to spin down, drawing fuel/air mixture through the carburetor and pushing it through the combustion chamber where there is no spark to ignite it, and into the glowing hot exhaust, where it would ignite and go BANG. I decided to approach it from the fuel/air end by shutting off the fuel first and leaving the spark running. All it took was disconnecting the wire from the M terminal at the ignition switch. When turning the key off, the spark plugs keep firing, but the fuel shutoff solenoid closes and the engine runs out of gas in a few seconds. No more bang. I did wire in a separate kill switch for the ignition, but I have never had to use it, and it's been quite a few years.My nerves and ears are are much happier.
I hope that helps someone.
I haven't been around much for quite a while, but a recent thread reminded me of a problem I solved quite a few years ago: The dreaded backfire a few seconds after shutdown. Maybe somebody else already did this, but I'll go ahead anyway.
It occurred to me that turning off the ignition on a hot engine allows the engine to spin down, drawing fuel/air mixture through the carburetor and pushing it through the combustion chamber where there is no spark to ignite it, and into the glowing hot exhaust, where it would ignite and go BANG. I decided to approach it from the fuel/air end by shutting off the fuel first and leaving the spark running. All it took was disconnecting the wire from the M terminal at the ignition switch. When turning the key off, the spark plugs keep firing, but the fuel shutoff solenoid closes and the engine runs out of gas in a few seconds. No more bang. I did wire in a separate kill switch for the ignition, but I have never had to use it, and it's been quite a few years.My nerves and ears are are much happier.
I hope that helps someone.