Startup difficulty or failure. The main symptoms or reasons are :(1) the engine of the starter has normal speed, but does not catch fire, or after a long time to start can catch fire. (2) The electrical system is faulty, mainly because the battery voltage is too low to start the ignition. (3) The intake system is faulty, mainly because the intake resistance exceeds the technical specifications, resulting in difficult to start or can not start without fire. (4) The crankshaft does not turn, which may be axle holding, cylinder biting, or other abnormal conditions, which can lead to difficulty or failure to start. In addition, sometimes because the oil level in the tank is too low, it can also lead to the phenomenon of difficult or unable to start.