Posted in the regular kids ATV forum, trying here to. Long story short, I bought a new carb for an Eton txl50. Pushed start, fired right up. Died 20 secs later. Second attempt, started seemed like it was pulsing, rev high, then fall to almost an idle then it would shoot back up. I tried giving it gas, but the throttle seemed to have no affect at all. Hold it wide open and still was goin high to low and so on. Ran like that for about 5 mins. Then it died. Took forever to start again, but same results. Stock Eton impulse txl50. Please help!

 

Eton and Polaris are basically the same, not quite sure on some of the differences,but if it's revving up and going down on it's own,then sure sounds like crank seals are leaking air and leaning it out. Plus wouldn't hurt to do a compression check if you haven't done so..

 

Did do a comp check. Had 100lbs. I will check on the crank case. Any ideas why the throttle wasn't affecting it? The carbs were the same, needle position is the same. That puzzled me more than the reving up did.

 

As long as you can rule out the new carb's jetting,carb slide,slide needle hold down clip is in place,the throttle cable is ok, any kind of air leak can cause something like this. Intake manifold gasket leak or crack in the manifold itself,air leak at the base gasket,crank seals leaking. The Polaris manual shows it should have a minimum of 115 psi compression with throttle open and cranked over several times.

 

"slide needle hold down clip is in place,"

The needle is floating.
That's what I'm thinking.