When the engine malfunctions, troubleshooting may be difficult, but among the possible issues listed below, if a similar fault occurs, you can refer to the causes and their solutions.

　　Fault 1

　　Engine runs unevenly

　　Possible causes:

　　1. Low fuel pressure

　　Solution: Ensure there is enough fuel in the fuel tank. Check for any leaks in the fuel system. Check if the fuel line between the fuel tank and the fuel delivery pump is severely bent. Check for air in the fuel system. Check the fuel pressure. At full load speed, check if the fuel delivery pump is functioning properly. Check the pressure difference before and after the fuel filter element. If the fuel pressure drops, install a new fuel filter element.

　　2. Air in the fuel system

　　Solution: Find and repair any air leaks in the fuel system. Remove air from the fuel system.

　　3. Missing or broken fuel line between the injection pump and the injection valve

　　Solution: Install a new fuel line.

　　4. Incorrect valve clearance

　　Solution: Adjust the valve clearance. Refer to the testing and adjustment section.

　　Fault 2

　　Engine stalls at low speed

　　Possible causes:

　　1. Low fuel pressure

　　Solution: Ensure there is enough fuel in the fuel tank. Check for any leaks in the fuel system. Check if the fuel line between the fuel tank and the fuel delivery pump is severely bent. Check for air in the fuel system. Check the fuel pressure. At full load speed, check if the fuel delivery pump is functioning properly. Check the pressure difference before and after the fuel filter element. If the fuel pressure drops, install a new fuel filter element.

　　2. Engine idle speed is low

　　Solution: Adjust the governor.

　　3. Incorrect valve clearance

　　Solution: Adjust the valve clearance.

　　Fault 3

　　Engine speed suddenly changes

　　Possible causes:

　　1. Air in the fuel system

　　Solution: Find and repair any air leaks in the fuel system. Remove air from the fuel system.

　　2. Governor linkage cannot move freely

　　Solution: Clean all linkages. Clean the inside of the governor housing. Replace all damaged parts with new ones.

　　Fault 4

　　Engine power is insufficient

　　Possible causes:

　　1. Poor fuel quality

　　Solution: Drain the fuel from the fuel tank and install a new fuel filter element. Refill the fuel tank with high-quality fuel.

　　2. Low fuel pressure

　　Solution: Ensure there is enough fuel in the fuel tank. Check for any leaks in the fuel system. Check if the fuel line between the fuel tank and the fuel delivery pump is severely bent. Check for air in the fuel system. Check the fuel pressure. At full load speed, check if the fuel delivery pump is functioning properly. Check the pressure difference before and after the fuel filter element. If the fuel pressure drops, install a new fuel filter element.

　　3. Air in the fuel system

　　Solution: Find and repair any air leaks in the fuel system. Remove air from the fuel system.

　　4. Intake system leak

　　Solution: Check the pressure in the intake pipe. Check the air resistance of the air filter.

　　5. Incorrect fuel setting

　　Solution: Adjust the fuel setting if necessary.

　　6. Fuel adjustment linkage

　　Solution: Adjust the linkage to have full travel. Replace damaged or faulty parts.

　　7. Incorrect valve clearance

　　Solution: Adjust the valve clearance.

　　8. Fuel delivery pump filter screen blockage

　　Solution: Remove and clean the filter screen.