My 2000 Quadrunner 250 starts great when cold. Once hot it starts hard. I have two options at this point. 1) let it cool down or 2) hold the throttle wide open while starting it and it will eventually start. I've replaced the plug (properly gapped) and cleaned the air breather.
Thoughts???? Thanks!

 

I'd start with cleaning the carb.

 

Check the valve lash. If there isn't enough when the engine warms up one or both valves may not be closing completely.
Mike

 

Thanks guys, Ill look into both!