if the fuel tank is below half full the generator will not start as the pickup for fuel is at the half full height so as to not let you use all your fuel and not be able to get back home , if it will not turn over use the boost button on the dash while the engine is running to boost it to start , lastly check the house batteries with a volt meter to see if they are at least 12.0 volts , any lower and the starter may not engade