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Tractor Backfires

scilipoti's Avatar

Join Date: Aug 2005
Posts: 17

10-20-06, 05:16 AM   #1  
Tractor Backfires

I have a 20 hp sears garden tractor. In the summer and spring, when I use it for cutting grass, it runs fine. In the winter, I put a snow plow on it. As long as I'm not pushing too much snow, it's ok. However, when the I'm pushing heavy snow it often backfires. I've been told this can be corrected by changing the air/fuel mixure on the carburator. Would I want to set the mixture more or less lean?

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puey61's Avatar

Join Date: Apr 2004
Posts: 3,224

10-20-06, 02:28 PM   #2  
Well, a backfire indicates an ignition related trouble but with what you are trying to accomplish, generally, you would want to richen the fuel mixture. In other words, turn the main adjusting needle out. Usually a quarter turn more (from normal summer use) is all that should be required. BUT, if you are running this in the winter with an air filter you need to bear in mind the possibility of the air filter freezing over and thereby causing a rich condition and this will seem like a backfire but it is actually a rich condition due to air flow blockage. If your air filter uses a foam pre-filter, I recommend removing this for the winter and use only the paper air filter.

mla2ofus's Avatar

Join Date: Jan 2005
Posts: 478

10-20-06, 07:23 PM   #3  
I would take both air filters off for snow removal as there is no danger of dust. If you're blowing powder snow the air filter could get plugged causing a really rich fuel mixture. Just be sure to put them both back on when the snow is all gone.

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