28634 Mercury SCREW, FLUSH - DRIVE SHAFT HOUSING

Work carefully around an engine that is running. Engine parts that are hot, or parts that are moving, can cause personal injury.
Keep all parts clean from contaminants.Contaminants may cause rapid wear and shortened component life.
Care must be taken to ensure that fluids are contained during performance of inspection, maintenance, testing, adjusting and repair of the product. Be prepared to collect the fluid with suitable containers before opening any compartment or disassembling any component containing fluids.Refer to Special Publication, NENG2500, "Caterpillar Tools and Shop Products Guide" for tools and supplies suitable to collect and contain fluids on Caterpillar products.Dispose of all fluids according to local regulations and mandates.
Table 1
Tools Needed
Part Number Part Name Quantity
1U-5470 Engine Pressure Test Group 1
8J-7844 Adapter Fitting 1
3K-0360 O-Ring Seal 1
4M-5317 Reducing Bushing 1
Illustration 1 g00296486
1U-5470 Engine Pressure Test Group
The 1U-5470 Engine Pressure Test Group measures the oil pressure in the system. This engine tool group can read the oil pressure inside the oil gallery.Note: Refer to Special Instruction, SEHS8907, "Using the 1U-5470 Engine Pressure Test Group" for more information.
Illustration 2 g00708467
Oil Pressure Test Location
(1) Oil gallery plug
Remove oil gallery plug (1) from the side of the cylinder block.
Install the following Tools into the port in the left side of the engine: 1U-5470 Engine Pressure Test Group, 8J-7844 Adapter Fitting, 3K-0360 O-Ring Seal and 4M-5317 Reducing Bushing.
Start the engine. Run the engine with SAE 10W40 oil. Refer to Operation and Maintenance Manual, "Engine Oil" for the recommendations of engine oil.
Record the value of the engine oil pressure when the engine is at operating temperature and operating under full load. The minimum engine oil pressure should be approximately 250 kPa (36 psi). Minimum engine oil pressure at low idle rpm (750 to 850 rpm) should be approximately 100 kPa (15 psi). Maximum engine oil pressure should be approximately 600 kPa (88 psi) when the engine is at operating temperature and operating under full load condition.
Compare the recorded engine oil pressure with the oil pressure indicators on the instrument panel.
An engine oil pressure indicator that has a defect or an engine oil pressure sensor that has a defect can give a false indication of a low oil pressure or a high oil pressure. If there is a notable difference between the engine oil pressure readings make necessary repairs.
If you have determined that the engine oil pressure is low, then go to "Reasons For Low Engine Oil Pressure".
If you have determined that the engine oil pressure is high, refer to "Reason for High Engine Oil Pressure". Reasons For Low Engine Oil Pressure
Keep all parts clean from contaminants.Contaminants may cause rapid wear and shortened component life.
Care must be taken to ensure that fluids are contained during performance of inspection, maintenance, testing, adjusting and repair of the product. Be prepared to collect the fluid with suitable containers before opening any compartment or disassembling any component containing fluids.Refer to Special Publication, NENG2500, "Caterpillar Tools and Shop Products Guide" for tools and supplies suitable to collect and contain fluids on Caterpillar products.Dispose of all fluids according to local regulations and mandates.
Engine Oil Level Is Low
Check the engine oil level in the crankcase. The oil level can possibly be too far below the oil pump supply tube. This will cause the oil pump not to have the ability to supply enough lubrication to the engine components. If the engine oil level is low add engine oil in order to obtain the correct engine oil level. Refer to Operation and Maintenance Manual, "Engine Oil" for the recommendations of engine oil.The Engine Oil Pump Is Faulty
Check the following problems that may occur to the engine oil pump.
Air leakage in the supply side of the oil pump will also cause cavitation and loss of oil pressure. Check the supply side of the oil pump and make necessary repairs. For information on the repair of the engine oil pump, refer to Disassembly and Assembly, "Engine Oil Pump - Remove".
Oil pump gears that have too much wear will cause a reduction in oil pressure. Repair the engine oil pump. For information on the repair of the engine oil pump, refer to Disassembly and Assembly, "Engine Oil Pump - Remove". The Oil Pickup Tube Has A Leak Or A Restricted Inlet Screen
The inlet screen of the oil pickup tube for the engine oil pump can have a restriction. This restriction will cause cavitation and a loss of engine oil pressure. Check the inlet screen on the oil pickup tube and remove any material that may be restricting engine oil flow. Low engine oil pressure may also be the result of the oil pickup tube that is drawing in air. Check the joints of the oil pickup tube for cracks or a damaged O-ring seal. Remove the engine oil pan in order to gain access to the oil pickup tube and the oil screen. Refer to Disassembly and Assembly, "Engine Oil Pan - Remove and Install" for more information.