this is from the manual:
Engine does not start
Possible Problem Solution
out of fuel
Refill fuel tank
Contaminated fuel
Replace fuel
Glow plug is bad
Replace glow plug
No fuel flow
Check fuel lines for cracks, leaks, and holes. Replace fuel line if necessary.
Engine flooded
Remove glow plug and discharge fuel
Engine has overheated
Allow engine to cool, richen the fuel mixture and restart
Throttle valve isn't adjusted properly
Set idle to neutral and reset linkages according to radio and model manufacturer's specifications
Air cleaner is blocked
Check air filter. Clean or replace of necessary.