What is the adjustment method for the fuel supply angle of a four-cylinder diesel engine?

[VanEmersyn]

1. Remove the high-pressure fuel pipe of the first cylinder and connect a thin transparent hose with a small inner diameter to the fuel injection pump outlet. Set the throttle to the maximum position and rotate the crankshaft to expel air from the fuel line. Then, squeeze a few drops of oil from the small hose and let the tail of the hose remain oil-free for a period to observe the fuel injection. 2. Slowly rotate the flywheel while observing the fuel injection in the hose. When the oil level in the hose rises and just stops (i.e., the fuel injection pump has just stopped supplying fuel), immediately stop rotating the flywheel. 3. Observe whether the piston has just reached the top dead center position at this time (the cylinder head can be removed in advance to facilitate observation of the piston's upward position). If the fuel injection pump stops supplying fuel too early or continues supplying fuel for too long when the piston reaches top dead center, it indicates that the fuel supply advance angle is either too large or too small. Adjust it as much as possible to make it basically consistent, which is considered good.