LT250 Wierd problem

[Wisers]

Ok so i just bought this back last week. I was driving around for a while then i got off and went inside for a while... maybe 20 minutes. I came back out to start it so it idled for a second then out of no where went to full throttle. I turned off the kill switch and pulled the spark plug cap right off. The problem is it kept running for id say atleast for 10 seconds at full throttle (it seemd alot longer at the time) Does anyone have a reason why it would do this? Im completly clueless.

[Furnaps_86Lt]

Im guessing air leak somewhere... and it kept running after you pulled everything because once it gets so hot its just detonates on its own i think.. I could be wrong though.

[Wisers]

I was thinking the same thing but i had just came back out to start it again so it was pretty cold.
I was thinking its sucking air as well but the boot to the carb is good, where else could it get air from?

[jayhoy]

Sounds like crank seals,I had the same problem with my lt250. Replace the crank bearings while your in there

[superevil]

If it only reved out for a second and died i would say your gas tank petkok is probably clogged,but if it was really for like ten seconds i would say crank seal

[gogoquadzilla]

hmm i've had a 'low on gas' situation cause it to race like that for about 10 seconds but never more than that. as far as an air leak goes, it could be from a crack in the boot, any seal between the carb and intake, crank seals, base gasket, head gasket

[nd4speed]

no gas or too much air equals lean then it "diesels" and runs without spark because of heat and pressure. My friends did this when it ran out of gas and have had it happen to me when running the bowl dry and we both may very well have leaking crank seals but they still worked fine after adding gas. Tear it all apart or just get an in line fuel filter and look for clogs in the gas tank and carb jets. Then ride it till it blows up and then tear it apart.

[lt250racer]

Yes, it could very well be an air leak, GogoQuadzilla had named the possible leak sites...
I would check the obvious places first, Like: Carb cable sticking, Fuel delivery, & gunked carb.....

[Wisers]

Thanks guys the head gasket is bad so it could be leaking from there? Ill look into all new seals and such. The bike belonged to my friend before i got it and i know it has been blown up at least 3 times with out rebuilding the bottom end so im sure it needs a few things. Thanks again for all the advice.

[Mert]

have you tried starting it again since then, and did it do it again? any ways take some starting fluid and spray a little around the base of your jug, then around the crank case and all the places mentioned earlier, if it starts reving up when you spray you have an air leak