My neighbor gave me his old go-kart and I fixed it up. The engine is giving me problems, though. It is a typical 5HP Briggs engine. It had been rained on with no air filter so I tore it down and cleaned it out and put it back together with new gaskets. I think they might have run it bone dry of oil because there was no oil in the crankcase but the cylinder and rings looked ok to me. So did the valves. It turns over just fine. The carb was very cruddy and I soaked it in carb dip and put it back together with new gaskets and diaphram.
After I got it all back together I started it up and it ran decently for a few hours. But then it started to run worse and worse. I bought a new carb for it and installed it tonight but it obviously wasn't the problem. Even with the new carb and with fresh gas it will only run with the choke all the way on. The new carb doesn't have an idle adjustment screw so it seems like it can't be a fuel problem. What else could it be? The only thing left is spark and compression. It obviously has both of those because it runs and had plenty of power when it was running OK which indicates compression is probably OK. I made sure the gas cap isn't blocked.
Any ideas what I should check next? Or what I should recheck?
Thanks, Gary