Noticed today my little go-kart/dune buggy was really bogging badly at WOT, would stall on an incline, etc. I figured it was time for a fresh air filter.

Well, when I opened up the airbox, oil comes pouring out of it, I'd say about 3 or 4 ounces of it. Judging from how it would have to get blown UP the carburetor, which sits above the engine, and then up the intake tube a little more to the airbox, there must be something putting a lot of pressure on the oil. BTW, it's a Twister kart with a Tongjian (read: cheap no-name) 150cc OHV single. What could have gone wrong?

 

is there gas mixed into the oil? was there water in the oil in the crank?

 

Sounds like you're getting a lot of blow-by past the rings. If you're getting that much oil in the air filter, then there's a lot of pressure being sent through the crankcase breather into the filter.

 

Did you have it flipped over for anything like repairing a wheel or tire, crash! Severe inclines could also cause it especially if it is a little over filled.If every thing checks out(no gas or overfill in oil)they sell a catch can that they use for racing carts that you can adapt and it will save your air filter.

 

No, no gas mixed with the oil, it's a 4-stroke. It's never been rolled or anything like that, there is a fairly good slope out by where it's parked that we drive it up and over every time we take it out. I sort of doubt it since it's been over that one many times, never had a problem.

I did get one more thought. I pushed it pretty hard the last time I drove it, we're talking flat out on the country road a good couple miles. I suppose it's possible I overheated it and warped a ring or busted a seal somewhere?

In other words, should I replace the filter, clean out the intake tube, and keep on truckin, or have it looked at? It's good to hear that it may not be as bad as I thought...