2017 ktm 85sx. runs fine with new plug, after warm it rides for 5 to 10 mins then backfires and stops. Have replaced fuel from 40.1 to 50.1, Plug spark is weak after this happens, any ideas

SOURCE: starts runs min. or two then stops....

Go to toro.com then click customer care, then click manuals and parts. Type in model no. and download the owners manual. This should get you the spark and flywheel gap. Probably still something in the carb. Some orifices are very hard to find and to clean but they must be clean. Also check for dirt dopper nest in the muffler.

SOURCE: car runs fine for about 5 min then bogs backfires

have you had the catalytic converter checked?

SOURCE: craftsman riding lawnmower shuts off after 15 - 20 mins.

I have a Troy-Bilt push mower that does the same.

Try this - Run the mower until the point of quitting. Keep the hood up and be ready to remove the gas cap. As soon as you feel it start to stutter like it's going to quit, unscrew the gas cap and see if it comes back to life and doesn't quit.

If that works, then what is happening is that the gas in the carburetor bowl is getting depleted faster than the tank can provide it, possibly because of a clogged vent that's supposed to allow air back into the gas tank as gas is used.

You can try running with the gas cap not quite tight, to let some air seep in that way, but that's more prone to sloshing leaks. You could also try drilling a hole in the gas cap - about 3/16" is plenty, and stuffing a piece of natural sponge in to keep the gas in and dirt out. Synthetic sponge will deteriorate in gas.

Jim Parker

• 1041 Answers
• Posted on Jun 21, 2009

SOURCE: brand new honda lawnmower starts and runs fine then backfires

There should be 1 or 2 screws on the carb. You will probably have to remove the air breather to get to the screw(s). I've been seeing a lot of these types of questions, new equipment not running properly. Factory settings were not set properly.

When you find the screw(s), screw in a clockwise direction until it stops; DON'T SCREW DOWN TIGHT, JUST UNTIL IT STOPS. Then unscrew counter clockwise 1 1/4 turns. Try starting.

Continue this process, 1/4 turn at a time up to 2 1/2 full turns. If you forget where you are at on the turning process, start over by screwing back down. Then pick up process where you left off.

If you need further assistance, just let me know.

Jim

SOURCE: 2002 buell blast is running rough - missing - backfiring

Wow, my 2002 blast is doing the same thing, or at least it was untill it blew a hole through the exhaust and quit running all together. Time for a sportster.