47463 Mercruiser PLUG, EXPANSION - ENGINE COUPLING

Introduction
The problem that is identified below does not have a known permanent solution. Until a permanent solution is known, use the solution that is identified below.Problem
On occasion, some C4.4 engines have experienced hard starting issues because of loss of fuel prime. This issue has been observed occurring mainly in units that were exercised at intervals of more than one week.Solution
Caterpillar is aware of this problem, but a permanent repair has not been identified. As an interim action, use the fuel line check valves that are available to resolve C4.4 engine hard starting due to loss of fuel prime. These check valves have been proven effective for resolving the issue on multiple engines.Required Parts
Table 1
Qty Part Number Description
1 6B-5072(1) Adapter
1 6V-2481(1) Adapter Union
1 8T-6850(2) O-Ring Seal
1 126-9093 Seal
1 346-8992(3) Clamp
1 549-4137(2) Adapter
1 550-4578(3) Adapter
1 565-8344 Check Valve (M16 X 1.5 thread)
1 540-2934(4) Check Valve (1/2 - 14 NPTF)
1 540-2935(5) Check Valve (1/2 - 14 NPTF)
(1) The 6B-5072 Adapter and the 6V-2481 Adapter Union are used with the 267-9213 Fuel Lines Gp and 308-1813 Fuel Lines Gp.
(2) The 8T-6850 O-Ring Seal and 549-4137 Adapter are used with the 318-8064 Water Separator and Fuel Filter Gp, the 334-0808 Fuel Filter Gp, and the 337-6251 Water Separator and Fuel Filter Gp.
(3) The 346-8992 Clamp and 550-4578 Adapter are used with the 462-2883 Fuel Lines Gp, the 462-4087 Fuel Lines Gp, and the 484-8209 Fuel Lines Gp.
(4) This check valve is used for fuel lines that connect to bulkhead fittings in the engine base rail.
(5) This check valve is used for fuel lines that connect directly to the fuel tank.
Illustration 1 g06258903The 8T-6850 O-Ring Seal and 549-4137 Adapter are used with the 318-8064 Water Separator and Fuel Filter Gp, 334-0808 Fuel Filter Gp, and 337-6251 Water Separator and Fuel Filter Gp. Refer to Illustration 1 for the correct location.
Illustration 2 g06258048No adapter is needed for 438-7763 Fuel Filter Gp water separator and fuel. Refer to Illustration 2.Rework Procedure
Illustration 3 g06230273
Remove the fuel line.
Remove and discard the original fitting in the fuel filter base.
Illustration 4 g06338650
(1) 126-9093 Seal
(2) 565-8344 Check Valve (M16 X 1.5 thread)
Apply O-ring lubrication to seal (1).
Install one seal (1) onto fuel supply check valve (2).Note: Make sure that the chamfer on the seal is facing towards threads (flat face of seal seats on flat face of check valve).Note: The 8T-6850 O-Ring Seal and 549-4137 Adapter are used with 318-8064 Water Separator and Fuel Filter Gp, 334-0808 Fuel Filter Gp, and 337-6251 Water Separator and Fuel Filter Gp.
Install fuel supply check valve (2) into the fuel filter base.Note: Even though the 565-8344 Check Valve with M16 X 1.5 thread will thread into the filter base shown in Illustration 1, 8T-6850 O-Ring Seal and 549-4137 Adapter are required due to different sealing geometry for this style filter base.
Install the fuel line onto fuel supply check valve (2).
Make sure that the fuel line does not rub or interfere with anything due to extra valve length.
Illustration 5 g06230276
(3) 540-2935 Check Valve (1/2 - 14 NPTF)
Remove and discard the original adapter between the fuel return line and fuel tank. Set aside the hose for reuse.Note: Use Loctite® 567 on all pipe thread joints.
Install fuel return check valve (3).The 6B-5072 Adapter and the 6V-2481 Adapter Union are used with the 267-9213 Fuel Lines Gp and 308-1813 Fuel Lines Gp.The 346-8992 Clamp and 550-4578 Adapter are used with 462-2883 Fuel Lines Gp, 462-4087 Fuel Lines Gp, and 484-8209 Fuel Lines Gp.Note: For bulkhead applications, use the 540-2934 Check Valve (M16 X 1.5 thread).
Attach the original hose to fuel return check valve (3).Note: Fuel line length adjustment may be required. After the check valve is installed, make sure that the fuel line does not rub or contact anything. Also, make sure that the fuel line is not pinched.