So many things to check, look for the driveshaft turning and turns fast? Next is the stuff we all talk to death, compression and fuel system condition, anyplace air comes in reduces or stops the fuel flow, take some time to clean the water/fuel bowl and look for signs of previous leakage including ugly lines bent at sharp angle could block flow, if you have compression above 125 pull the choke and see if any burbs of barks - NEVER use a running car or battery charger on high to overcome a weak battery, wait for it to charge up and give the hull a chance to clear the fumes.