Ive had issues with mine not priming. It ends up being in the kill switch. Sometimes you just have to press or depress the switch forcefully for it to recognize what position its in. dont try to start it until you here the fuel pump, it wont go. Ive had several days where ive taken it to the shop and told em the problem, they looked over the electrical system, starter system, and determined it had to be the switch. Mess with the switch a bit when the problem is occurring and it seems to resolve.

 

check your engine stop relay. My fuel pump wouldn't kick on at all, then i replaced this relay and it worked fine. also flip your engine stop switch a few times, and make sure its working right.