899912027 Mercury TAPPET, (3.538)

Sulfuric Acid Burn Hazard may cause serious personal injury or death.The exhaust gas cooler may contain a small amount of sulfuric acid. The use of fuel with sulfur levels greater than 15 ppm may increase the amount of sulfuric acid formed. The sulfuric acid may spill from the cooler during service of the engine. The sulfuric acid will burn the eyes, skin and clothing on contact. Always wear the appropriate personal protective equipment (PPE) that is noted on a material safety data sheet (MSDS) for sulfuric acid. Always follow the directions for first aid that are noted on a material safety data sheet (MSDS) for sulfuric acid.
Note: Plug or cap all open ports with new plugs or caps.
Drain the coolant from the cooling system into a suitable container for storage or disposal. Refer to Operation and Maintenance Manual, "Coolant - Change" for the correct procedure.
Illustration 1 g06523877
Typical example
Disconnect the Original Equipment Manufacturer (OEM) harness assembly from engine harness connector (6).
Remove nut and washer (5) from harness assembly (18). Remove bolts (3) from bracket (4). Remove the engine wiring harness assembly (18) from bracket (4). Position the harness assembly away from the bracket (2) (not shown).
Cut cable strap (15) from harness assembly (1) for temperature sensor (13). Disconnect the harness assembly from the engine wiring harness.
Cut the cable strap and disconnect harness assembly (8) for inlet air throttle valve (9).
Remove nut (16) from terminal (17)
Remove bolts (11) from bracket assembly (2) (not shown). Remove the bracket assembly.
Use suitable tooling to expand clamp (10) and move the clamp along hose assembly (12) away from elbow connection (7) for the NOx Reduction System (NRS) cooler assembly. Disconnect the hose assembly from the elbow connection.
If necessary, use suitable tooling to expand clamp (14) and move the clamp along hose assembly (12) away from the cylinder head. Disconnect the hose assembly from the cylinder head connection.
Illustration 2 g06320991
Typical example
Illustration 3 g06321038
Typical example
Remove bolts (20) from exhaust cooler assembly (19).
Disconnect harness assembly (24) from the NRS Valve (23).
Disconnect harness assembly (26) from differential temperature and absolute pressure sensor (25).
Illustration 4 g06383497
Disconnect the OEM hose assembly from connection cooling system air vent (29)
Cut cable strap (27) for the engine harness assembly.
Remove bolt (32) and nuts (30) from exhaust cooler assembly (19).
Remove exhaust cooler assembly (19) from the cylinder head (28) and inlet elbow (22). Remove gasket (31) (not shown) and gasket (21) (not shown).
If necessary, remove differential temperature and absolute pressure sensor (25) from exhaust cooler assembly (19). Refer to Disassembly and Assembly, Pressure Sensor (NRS Absolute) - Remove and Install for the correct procedure.Installation Procedure
Check all components for wear and damage. If necessary, replace any components that are worn or damaged.Note: Remove plugs and caps that were previously installed prior to assembly.
Ensure that the NRS exhaust cooler is free from restriction and external damage. Ensure that the NRS exhaust cooler and tube assemblies are free from wear and damage. Refer to Systems Operation Testing and Adjusting, "Exhaust Cooler (NRS) - Test" for the correct inspection procedure.Note: The NRS exhaust cooler, should not be internally cleaned.
Illustration 5 g06320991
Typical example
Illustration 6 g06321038
Typical example
Illustration 7 g06321358
Tightening sequence for exhaust cooler assembly
If necessary, install differential temperature and absolute pressure sensor (25) to exhaust cooler assembly (19). Refer to Disassembly and Assembly, Pressure Sensor (Cooled Exhaust Gas) - Remove and Install for the correct procedure.
Position new gasket (31) (not shown) onto the cylinder head (28). Ensure that the gasket is correctly orientated and is correctly installed onto the studs.
Install new gasket (21) (not shown) onto exhaust cooler assembly (19). Ensure that the gasket is correctly positioned onto the exhaust cooler assembly.
Position exhaust cooler assembly (19) onto the cylinder head (28) and inlet elbow connection (22).
Install bolts (20) to exhaust cooler assembly (19). Hand tighten the bolts. Refer to Illustration 5
Install bolt (32) and nuts (30), to exhaust cooler assembly (19). Hand tighten the bolt and nuts. Refer to Illustration 6.
Tighten bolts (32) and (20), nuts (30), to a torque of 22 N m (195 lb in) in the sequence shown in Illustration 7.
Connect harness assembly (24) to NRS Valve (23).
Connect harness assembly (26) to differential temperature and absolute pressure sensor (25).
Install new cable strap (27) to the engine harness assembly.Note: Ensure that the cable strap meets the Original Equipment Manufacturer (OEM) specification.