hot starting problem

[red and white]

300 mxu will not restart after warm up. Any help would be great. Thanks

[ophelia]

Does it catch and stumble and run a little bit? Or does it just turn over with no signs of combustion? Does it start if you crack the throttle open just a little bit?

How does the spark plug look?
How are your valve clearances?
If you open the gas cap, do you hear a vacuum being released?

edit: I took a look at the owners manual. Is the choke fully off and throttle opened a crack?

If you cannot restart a warm engine:
1. Follow steps 1 through 4.
2. Open the throttle slightly (1/8 - 1/4) while
starting the engine . If the throttle limiter Is
adjusted as delivered, open the throttle fully.

STARTING A WARM ENGINE
To start a warm engine, refer to the "Starting a
cold engine" section. The choke knob should not
be used. The throttle should be opened slightly.

[red and white]

yes it does catch and stumble a little bit. Valve clearances are right on. Giving it 1/8 throttle it sometimes fires, but never takes off.

[ophelia]

Are you getting a strong spark when the ATV is hot? In case the resistances in the various components of the ignition system are varying out of spec once the machine warms up.

I also wonder if fuel is getting to the carburetor.

Have you had trouble with it before?