My 500 Scrambler 2x4 backfires. It happens mostly when the engine is idling at a high rate. I can adjust the throttel (thumb screw) cable at the throttle control but it does not stay set. Is there an adjustment that can be made at the carburetor?

 

first thing make sure you have only 1/8" play in your thumb throttle, it adjusts up the cable 4". pull back the protective sheath.too loose or too tight will make it run bad. then you can adjust at carb. there is alittle **** that should be faceing left at the carb,when you adjust go back and make sure thumb throttle is still 1/8" play..

 

Thank you for the help - I will give it shot.

 

How would the engine idle speed or throttle cable adjustment give it the backfire problem? Seems like it is either running rich or lean to have that sort of problem.
I am just asking.

 

unless the cable was too tight it shouldnt be causing the high rev and not dropping back down. if messsing w/ the cable doesnt bring it down, you may have air leak which is causing the high idle. check the carb boot for cracks or being loose. just an idea.