Here it is, I finally got my LT started lastnight. It was Idleing irratically and revving higher than normal, so I turned it off. Started it again and it was Idleing a little better, so I start blippin the throttle and its doin good, I put it in gear and the RPM's just take off like a BAT OUT OF HE!!, so I pull the tether switch, doesn't stop! So I pull the Plug wire and it still doesn't stop!!! SO I am freakin tryin to figure how it can run with no spark, so I take my last resort and RIP the Carb out of it. Finally it stops but now I not sure what the heck happend. here is all the info I think could affect it,

Weather was about 50 degrees
Jetting is done propper(280 main) from b4 tear down
carb was cleaned out the day b4
new spark plug(BR8EG) and after the revving it was tan,
altitude was about 3000

Any help would be appriciated

 

Maybe an air leak or the slide is stuck allowing fuel into the engine when no throttle is applied. Sounds like you have got the main jet right if you have no air leak!

 

Holy crap, I havent a clue how it can go with no spark. That kinda freaks me out, how long did it run without a spark? Was it just like a second, or a long time? Wow, kinda scary! Would hate to be racin and going into a turn and all of a sudden it takes off on me or something!

 

Definitely sounds like an air leak, if it's revving up by itself or irratically.

It ran without spark on the same basis how model airplane engines run. Very similar to diesel engines as well. It's continually compressing gas (and the cylinder may be extremely warm) so that it continues to burn. I just never heard of a quad doing it! LOL

 

It ran for more than a bit, it ran long enuf for me to jump of the quad, look at it in amazment, then grab ahold of the carb and pull. It might have been a air leak, but could it be on the carb boot? Or is it more than likely to be one of my gaskets? Or a Crank Seal?

 

Ive seen a 300 bayou run wit out a spark. It was stuck and we was boring the crap out of it and it just got so out u could turn it off we pulled the plug wire off and everything.

 

I've seen bikes "diesel" with no spark, it's a scary thing too, you just sit and wait for your bike to spit pieces everywhere. I know on my LT, it has an erratic idle and runs erratically when it is low on fuel, which could also show up as an air leak causing a lean mixture (this could keep the cylinder temperature high enough to diesel along) or like an old car does with carbon deposits on its valves after you turn the key off, it keeps knockin along for a while. I would do a leak down test on the bike, and find the air leak. Check your carb to see if the slide moves freely also, but I don't think that is your prob. Later.

 

would a loose airboot cause this? I think they were loose cause the carb ripped out of it pretty damn easy

 

Dude im guessing the Basegasket is leakin air bad, check it out, one time my gasket was blown out on my blaster it started revving really high and kept getting higgher so i turned the kill switch off and it didnt stop then i took the key off and it still did it. so i just let the clutch out and stalled it which is what u should have done but u probl was thinking that then hehe.

 

It runs, and I mean normal now, my boot between the carb and reedcage was cracked, so I snached one off of my builder quad, runs great now. Thanks for all the help and hope to hit the trails now! If this damn weather would lift.