backfire
 

123 backfires everytime i shut her down just before she goes out. sometimes after runnin her long periods she will backfire two maybe three time at the most. ????

My freind's 123 and 129 both do that. I have a off topic that always does it. If it runs fine otherwise, it's just excess fuel in the muffler from shutting down.
My CCO does it only when I run out the fuel lines when I plan on parking it for more than a few weeks..

I hear ya, Jay. My 100 was backfiring, when I ran it out of gas the other day hauling leaves...lol.

Do you let it idle down at low idle for about a minute or two before shutting it off? If not try that. Even my 128 will do that if I just shut it off quickly. Letting it "cool" down usually helps a lot just before shutting it off.

DX3's suggestion will cure the problem. It's just the nature of some beasts.

my 1200 was backfiring like that too when i got it running . When i finally set timing with ohmmeter, engine temp dropped dramatically, started much easier, and backfiring stopped. Even right after working it HARD.

Here is a nice little writeup about "after-fire" ..



http://cubfaq.com/backfire.html


Jeff (teet)

thanks guys. its been doin it forever. runs great otherwise. i have tried the idle down and it still does it. but its not a big deal. just wonderin if it was somethin off. i read that article on carbon build up. was thinkin of taking that chore on someday.