i checked the carb, it closed completely.

This is what happened today,
I started it up without a problem. As long i keep the rpm under 5000, i saw the right muffler puff while smoke once awhile, the air came was not at a constant rate. Once rerv up to 6000 rpm, the engine kick automatically to 10000 rmp and stay there (it wont go down at all). I tried to turn off the engine by turning the key, but the engine keep running. I worried that it's going to over heat state. Then i turned off the gas and took the gasoline tank out. It still rerving at 10,000 rmp (even when key turn off, gas tank is out) for 5 mins, then one of the radiator hose that goes to the clutch break loose and fluid flying everywhere. After 1 min after the fluid is empty out, it's finally shut down with smoke and smell.

what could be the problem?

One more question:

where can i buy this

6 19410-KV3-000 Pipe COMP. distributor on top of the clutch?

is there a website?

thank you very much for helping me out.