930111-0500 Tohatsu NUT

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.
The low-pressure fuel system can be pressurized for a time period after the engine has stopped operating. The operating pressure of the low-pressure fuel system can be 500 kPa (73 psi). Caterpillar recommends that the secondary fuel filters should be drained before any maintenance of the low-pressure fuel system is carried out.
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.
Illustration 1 g03347228
Typical example
If necessary, remove the low-pressure fuel line from the retaining clips. Remove the low-pressure fuel line (1) from the inlet connection of the secondary fuel filter base and the fuel transfer pump. Note: Ensure that the low-pressure fuel lines are not deformed.
Connect Tooling (A), suitable tube assemblies, and connections between the fuel transfer pump and the secondary fuel filter base. Ensure that Tooling (A) is secured and clear of rotating parts.
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 10.a to 10.d for the procedure for testing the air in fuel.
Run the engine a low idle speed.
Illustration 2 g00578151
Typical example of 2P-8278 Tube As (Sight Gauge)
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.
Investigate potential leaks and rectify any potential leaks in the low-pressure fuel system. Check for leaks between the fuel tank and the inlet at the fuel transfer pump. If necessary, replace the low-pressure fuel lines.
Remove Tooling (A), the suitable tube assemblies, and connections. Reconnect the low-pressure fuel line.
Prime the fuel system. Refer to Operation and Maintenance Manual, "Fuel System - Prime" for the correct procedure.