I recently had a '97 Bayou 300 4X4 4 stroke basically dropped in my lap. I am about to pull my hair out because of it(no wonder it was such a great deal). The previous owner said it started acting up so he parked it since he had other wheelers to use. It sat for about a year. He described the problem as backfiring through the carb and dying especially at idle. When I got it home I: put in new battery, removed and cleaned gas tank, removed and rebuilt carb, checked timing chain, checked valve play, tested spark.
Here's the problem/s and for all these it doesn't matter if it is warmed up or not (outside temp 65F): 1/2 the time it will start without choke on, 1/2 the time has to be choked. Sometimes it will fire up right away other times you have to crank over and over up to a minute (in about 6-8 second tries). When it does start, sometimes it idles fine others you have to turn the idle way up to keep it running. Sometimes when you touch the throttle it will pop through the carb and then sputter until it dies other times it accelerates just fine. Part of the time it will hold higher RPMs with the throttle fine others it will again sputter and die. When it does die it still goes back to the 1/2 and 1/2 choke problem and the start/not start right away problem. The times that I can keep it running, if I give it 1/2 to full throttle the exhaust it a brownish color. I check the spark plug (several new ones) and they come out of the engine with a very little black color except for the electrodes which are the same metallic color as a new unused one.
I am open to any suggestions and am more than willing to buy a beer (or six) for the person who gives me the cure that fixes the wheeler. (and replacing the whole thing isn't a fix, that's just passing off the problem)
Thank you in advance,