The overhaul kit generally includes: (1) Front and rear crankshaft oil seals, oil pan gaskets, cylinder gaskets, valve cover gaskets, intake and exhaust manifold gaskets, valve oil seals, water pump gaskets, camshaft oil seals, oil nozzle upper and lower oil rings, gasoline filter. There are also some small cover gaskets, depending on model and engine model. (2) Ignition part: If the high-voltage line is swollen or leaks electricity, replace the ignition piston. (3) Part near the air: air filter. (4) Clean the oil circuit, maintain the motor, and maintain the generator.