my riding mower back fires

Sun Mar 28, 2004 4:23 pm

my riding mower back fires every time i turn it off, whats wrong

Sun Mar 28, 2004 4:45 pm

Unburned fuel is reaching the hot muffler and being ignited. You can let it run at idle a little while to cool down or try cutting the fuel off if you have a shut-off valve. It probably won't hurt anything unless it is a violent backfire.

Sun Mar 28, 2004 5:50 pm

Used to have a Case riding mower that had the same problem. Sometimes you would get half way off before it did. Used to scare the daylights out of me (10x10 metal building). Never did find a solution (cooling didn't help), but it didn't seem to hurt anything, other than testing the muffler strength.

Sun Mar 28, 2004 6:08 pm

Well you did not give us a clue as to what mower or engine you have in your post. SO I am going to go out on a limb and guess that it is a newer model with an electronically controlled carb. If so the way to stop it from backfiring is to shut it off with the throttle 1/2-to-3/4 open.

re back fire

Sun Mar 28, 2004 6:55 pm

I have a 1989 MTD 11 horse with B&S engine that has been doing this for awhile now.I have tried adjusting carb,and ideling down before I shut of. I also only use mid grade gas .. Nothing seems to stop the backfire.I also would be interested in a solution :D

re my riding mower keeps backfiring

Sun Mar 28, 2004 9:35 pm

thanks for the help so far, i'm glad to see its not just my mower Ihave tried all different ways to stop it from backfiring pulling out the choke till the motor dies helps sometimes but not always, someone asked what kind of mower it was it's a yard king from lowes with a 15.5 hp B&S engine 3 years old I'm keep thinking the motor is going to explode

thanks again

Sun Mar 28, 2004 9:42 pm

I think you have the electric shut off solonoid on a three year old briggs. You can tell by looking to see if there are wires going to the carb. If so try shutting it off when it is running at 1/2 throttle or more, That stops the backfiring for me.

Mon Mar 29, 2004 6:59 pm

Check your carb and exhaust manifold gaskets. It can be possible to suck and blow at the same time....

Just a thought.


Thu Apr 29, 2004 10:00 pm

hey looks like setting the throttle at half way fixes the problem

thanks for all the help

Fri Apr 30, 2004 11:47 am

Used to have a Case riding mower that had the same problem.

That's what my Case 222 did... for about 20 years. It was sinister, because it would wait long enough to fool you. Just when you believed it wasn't going to do it this time ................................BANG!