Hello. I have a 1996 Kawasaki bayou 300 4 wheeler that I cannot get to run.

I bought this 4 wheeler on craigslist and I can not get it to work at all.

I re-timed it, I bought a brand new carb, I have adjusted valves. I have gotten the engine to the point it ONLY starts when I cut off the air-flow to the carb in the air box and it will run for maybe a few seconds and then cut off. It revs very poorly when it does cut on.