3C8-01291-0 Tohatsu LOWER HEAD, CRANK CASE

Visual Inspection
Inspect the following parts at each oil change:
Air lines
Hoses
Gasket joints
Pressurized air can cause personal injury. When pressurized air is used for cleaning, wear a protective face shield, protective clothing, and protective shoes.
Ensure that the constant torque hose clamps are tightened to the correct torque. Refer to Operation and Maintenance Manual, "Standard Torque for Constant Torque Hose Clamps" for the correct torque. Check the welded joints for cracks. Ensure that the brackets are tightened in the correct positions. Ensure that the brackets are in good condition. Use compressed air to clean any debris or any dust from the aftercooler core assembly. Inspect the fins of an air to air aftercooler for the following conditions:
Damage
Debris
CorrosionUse a stainless steel brush to remove any corrosion.Note: When parts of the air-to-air aftercooler system are repaired or replaced, a leak test is recommended.Inlet Manifold Pressure
Normal inlet manifold pressure with high exhaust temperature can be caused by blockage of the aftercooler core. Clean the aftercooler core.Low inlet manifold pressure and high exhaust manifold temperature can be caused by any of the following conditions:Plugged air cleaner - Clean the air cleaner or replace the air cleaner, as required. Refer to the Operation and Maintenance Manual, "Engine Air Cleaner Element - Clean/Replace".Blockage in the air lines - Blockage in the air lines between the air cleaner and the turbocharger must be removed.Aftercooler core leakage - Aftercooler core leakage should be pressure tested. Refer to "Aftercooler Core Leakage" under this topic for the testing procedure.Inlet manifold leak - An inlet manifold leak can be caused by the following conditions: loose fittings and plugs, missing fittings and plugs, damaged fittings and plugs and leaking inlet manifold gasket.Aftercooler Core Leakage
A low power problem in the engine can be the result of aftercooler leakage. Aftercooler system leakage can result in the following problems:
Low power
Low boost pressure
Black smoke
High exhaust temperature
Remove all air leaks from the system to prevent engine damage. In some operating conditions, the engine can pull a manifold vacuum for short periods of time. A leak in the aftercooler or air lines can let dirt and other foreign material into the engine and cause rapid wear and/or damage to engine parts.
A large leak of the aftercooler core can often be found by making a visual inspection. To check for smaller leaks, use the following procedures:Leak Test for Air to Air Aftercoolers
Illustration 1 g00295702
FT-1984 Aftercooler Testing Group (1) Regulator and valve assembly (2) Nipple (3) Relief valve (4) Tee (5) Coupler (6) Aftercooler (7) Dust plug (8) Dust plug (9) Chain
Disconnect the air pipes from the inlet and outlet side of the aftercooler core.
Illustration 2 g00298658
A typical example of the tooling that is installed is shown above. (1) Coupler (2) Chain (3) Dust plug
Dust plug chains must be installed to the aftercooler core or to the radiator brackets to prevent possible injury while you are testing. Do not stand in front of the dust plugs while you are testing.
Install couplers (1) on each side of the aftercooler core. Also, install dust plugs (3) .These items are included with the FT-1984 Aftercooler Testing Group .Note: Installation of additional hose clamps on the hump hoses is recommended in order to prevent the hoses from bulging while the aftercooler core is being pressurized.
Do not use more than 240 kPa (35 psi) of air pressure or damage to the aftercooler core can be the result.
Illustration 3 g00298678
(5) Regulator and valve assembly.
Install the regulator and valve assembly (5) on the outlet side of the aftercooler core assembly. Also, attach the air supply.
Open the air valve and pressurize the aftercooler to 205 kPa (30 psi). Shut off the air supply.
Inspect all connection points for air leakage.
The pressure in the aftercooler system should not drop more than 35 kPa (5 psi) in 15 seconds.
If the pressure drop is more than the specified amount, use a solution of soap and water to check all areas for leakage. Look for air bubbles that will identify possible leaks. Replace the aftercooler core, or repair the aftercooler core, as needed.
To help prevent personal injury when the tooling is removed, relieve all pressure in the system