Mag 18 Backfires and Dies
 

Hello Old Friends!

I have a 782 that I repowered with a Magnum 18 that currently has about 550 hours on it.

While mowing it will run fine for a while, but after running about an hour, it will begin to backfire through the muffler and die out. Will not restart until after it has cooled down a while.

It’s been so long since I have worked on it that I don’t know where to start. Can anyone provide input on what I should look at first?

Any ideas would be greatly appreciated.

Thank you!
Steven C.
Nashville

If it won't start til it cools its likely losing spark. Run it till it shuts off and check the spark.

Getting hot? Have you checked for debris under tins? Fire through exhaust is typically valve not seating or lean condition.

I agree with the others and I would also add that maybe you have something causing lean conditions such as fuel filter blockage or gas cap not venting.

After you check for spark, and if it has it, then check the screen inside the gas tank.

My 1872 did something similar a few years back and it had green crap in the fuel bowl.