Have a year old Tao Tao 125 atk go kart with a 3 speed transmission plus reverse. Starts up and runs great for about 10 minutes then looses power and dies when I attempt to restart it struggles to turn over the engine, almost acts like there is to much compression and it turns really slow. If I let it cool of it will start again and run good until the engine gets hot then it does the same thing over again. Any help would be greatly appreciated.

So far i have done the following:

Cleaned the Carb
Checked the Valve gaps
Checked the Starter

 

Sounds like it is seizing, check the oil level. If that is OK, check the transmission isn't dragging when hot, and is the cooling system working?

 

Oil level is good, I change the oil regularly.
When put in neutral I have the same issue so I am pretty sure it is not the transmission.
Engine is air-cooled so I think I am good there.

My initial fear is that it is seizing as well, once the engine is hot it loses power before it cuts out and then really struggles to turn the engine over until it cools down.