12251-ZW9-003 Honda GASKET, CYLINDER HEAD (Honda Code 6639223).

Ensure that all adjustments and repairs that are carried out to the fuel system are performed by authorized personnel that have the correct training.Before beginning ANY work on the fuel system, refer to Operation and Maintenance Manual, "General Hazard Information and High Pressure Fuel Lines" for safety information.Refer to Systems Operation, Testing and Adjusting, "Cleanliness of Fuel System Components" for detailed information on the standards of cleanliness that must be observed during ALL work on the fuel system.
Note: Ensure that the tools are stored with the caps in place. Store the tools in a clean plastic bag.
Ensure that the fuel level in the fuel tank is above the level of the suction pipe in the fuel tank.
Inspect the fuel system thoroughly for leaks. If necessary, repair the fuel system.
Check all low-pressure fuel lines from the fuel tank for restrictions. Replace any damaged components.
Prime the fuel system. Refer to Operation and Maintenance Manual, "Fuel System - Prime" for the correct procedure.
Start the engine. Refer to Operation and Maintenance Manual, "Starting the Engine" for the correct procedure. Check if the problem has been resolved. Run the engine at low idle speed for 5 minutes.
Stop the engine. Refer to Operation and Maintenance Manual, "Stopping the Engine" for the correct procedure.
Work carefully around an engine that is running. Engine parts that are hot, or parts that are moving, can cause personal injury.
Install Tooling (A) in the fuel return line. When possible, install Tooling (A) in a straight section of the fuel line that is at least 304.8 mm (12 inches) long. Do not install the sight gauge near the following devices that create turbulence:
Elbows
Relief valves
Check valves
Connections
Prime the fuel system. Refer to Operation and Maintenance Manual, "Fuel System - Prime" for the correct procedure.
Start the engine. Refer to Operation and Maintenance Manual, "Starting the Engine" for the correct procedure. Refer to steps 9a to 9h for the procedure for testing the air in fuel.
Run the engine a low idle speed.
Run the engine for 2 minutes. There should be no air in the fuel flow through the sight gauge. Small bubbles that are spaced more than 2.5 cm (1.0 inch) are acceptable. Do not manipulate the connections during the test for the air in fuel.
The presence of large bubbles or a continuous stream of bubbles indicates a leak.
If excessive air is seen in the sight gauge in the fuel return line, install a second sight gauge at the inlet to the fuel filter/water separator. If a second sight gauge is not available, move the sight gauge from the fuel return line and install the sight gauge at the inlet to the fuel filter/water separator.
Run the engine a low idle speed.
Run the engine for 2 minutes. There should be no air in the fuel flow through the sight gauge. Small bubbles that are spaced more than 2.5 cm (1.0 inch) are acceptable. Do not manipulate the connections during the test for the air in fuel.
The presence of large bubbles or a continuous stream of bubbles indicates a leak.Note: If excessive air is seen at the inlet to the fuel filter/water separator, air is entering through the suction side of the fuel system.
Investigate potential leaks and rectify any potential leaks in the low-pressure fuel system. If necessary, replace the low-pressure fuel lines.
Remove Tooling (A). Reconnect the low-pressure lines.
Prime the fuel system. Refer to Operation and Maintenance Manual, "Fuel System - Prime" for the correct procedure.