Ask the Mechanic

Steve Thompson, Contributing Columnist

Be extra careful when filling a propane tractor with the engine running. A generator, unlike an alternator, throws sparks from the back from the brushes. This can ignite the propane fumes coming out of the bleeder valve or a small leak from the filler hose connection. Spilled gas also can be ignited by the generator.

My father-in-law ran a John Deere 3020 (generator) on propane (never liked to start hot) until it burned to the ground. While allowing the tractor to run during filling, a small leak at the tank coupling caught fire. He got on the tractor and backed up to get away from the fire, pulling the hose out of the burning fitting. Next, the bleeder valve caught fire, allowing the fire to spread even more. Finally, the heat was so intense, it blew out the safety valve on the tank.

I was in the field on another tractor when that happened, and I can still see that flame shooting out of the propane tank. Unfortunately, he had canceled the insurance on that tractor two weeks before this happened. Thank goodness for a good cotton crop that year.

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-- Email Steve Thompson care of askthemechaniccolumn@gmail.com, and be sure to include your contact information and phone number.

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