I have an old 2000 Honda Recon, and it doesn't seem to want to stay running. The engine turns over and will run if I hit the throttle, but eventually it backfires and dies. I cleaned out the gas tank and freed up the petcock, and there is gas flowing. What should I try next?

 

Is the vent in the filler cap blocked? When it starts to misfire, slacken the cap, a sucking sound and instant cure of the misfire means the vent is blocked. If it isn't that, try cleaning the carb out, it can't hurt.