Engine flameout / rotation uneven fault detailed
1) Check the spark plug of the ignition system. When the engine is idling, press the tip of the wooden handle or screwdriver on the cylinder head or the metal shell of the engine itself, and touch the wire end of each spark plug with the metal part of the screwdriver, as the engine gradually If it slows down, it means that the spark plug works under normal conditions. If the engine speed does not change, the spark plug fails or the compression of the engine itself is not ideal.
2) If the spark plug is intact and the engine still has a flameout phenomenon, it may be caused by a dent or ablation of the power-off point. An excessively large power-off point indicates that the distributor has lost its usefulness.
3) Failure of the fuel supply system
4) The valve or gap adjustment is improperly adjusted –
a) The carburetor is not properly adjusted. When the engine is idling or running at high speed, the engine does not rotate slowly or the speed is not uniform, and tempering occurs after a considerable period of operation.
b) The gasoline is not completely burned, the engine runs unevenly when it is idling, and it cannot rotate at the time of acceleration. This difficulty is incomplete combustion. The unvaporized or incompletely burned gasoline dilutes the lubricant of the cylinder wall and crankshaft.
If abnormal noise is generated at the engine, it is very likely that the piston is blocked and the operation is difficult. At high speed, an appropriate amount of cylinder oil can be injected from the intake manifold to wash off the oil.
Piston ring and cylinder damage:
Start the engine and make it speed slightly higher than the idling speed, then listen carefully on the snorkel. If there is a slight squeaking sound, it indicates that the air pressure in the cylinder penetrates into the crankcase. If there is a greasy spark plug, it also means the piston ring. Damage has occurred with the cylinder wall.
Maintenance method: If the damage is excessive, the cylinder should be re-honed.
5) Air valve leakage: Air valve leakage is also one of the causes of engine stall or uneven speed. Want to test if the intake valve leaks? The handkerchief can be placed on the carburetor inlet, and if the gas is blown back from the leaking intake valve, the handkerchief is blown open. Is the exhaust valve leaking? The exhaust pipe can be listened to, and if there is a click, the exhaust valve is leaked.
Maintenance method: Re-grind the exhaust valve to make the clearance moderate.