View Full Version : Backfiring engine
07-01-2001, 09:12 PM
I've got a 12HP B&S engine on a Lowes/MTD riding mower. Periodicaly the engine backfires when I go around a corner, or when I disengage the blades and put the mower in neutral. Is this normal? This sort of thing happened to me before, and the engine ended up throwing a rod. I don't want that to happen again, any preventive advice, checks?
Ok try this
1.lower your RPM before shutting off the engine.
2. turn fuel shut off valve next to you gas tank and let the motor run itself out.
This works great for me with my Scag 36 in WB
07-08-2001, 08:03 AM
Or you can lift the battery up, slide the riding tractor out from under it and slide a commercial mower under it that has a real engine. Drop the battery into the commercial mower and wham, problem fixed.
07-17-2001, 01:27 PM
What sounds like is you may be getting an excess of fuel into the combustion chamber. What would normally cause this is the wrong float bowl setting. Get yourself a nice manual on 12HP Briggs engines and it will tell you how to go about doing it. Normally, you just remove the carb, remove the bowl on the bottom, turn it upside-down, then measure the distance between the bowl mounting surface and the bottom (in this position) of the float (usually not more than maybe 1/4" to 3/8") look at the book. There is a tab at the pivot side of the float which controls the depth of the needle valve. If you insert a screwdriver into or under that tab and bend it, you can achieve the desired height. Also, it never hurts to keep-up with regular maintenance such as spark plug, air cleaner, etc. Hope this helps.
Sounds like a layer of water in the bottom of the carb bowl. Dump
it out and see what happens.
Also could be that the kill wire to the switch at your forward
/reverse lever is has come unplugged and is close to metal.
Take the two phillips screws off of the panel and lift it up and
see. The seat switch is another problem area .
08-06-2001, 02:39 PM
Sounds like the seat switch to me.
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