52901 Mercury NUT, FLYWHEEL

This engine uses high voltage to control the fuel injectors.Disconnect electronic fuel injector enable circuit connector to prevent personal injury.Do not come in contact with the fuel injector terminals while the engine is running.
Note: Valve lash is measured between the rocker arm and the bridge for the inlet valves. Valve lash is measured between the rocker arm and the bridge for the exhaust valves. All of the clearance measurements and the adjustments must be made with the engine stopped. The valves must be fully closed.Valve Lash Check
An adjustment is not necessary if the measurement of the valve lash is in the acceptable range. Adjust the valve lash while the engine is stopped. The range is specified in Table 1.
Put the No. 1 piston at the top center position on the compression stroke. Refer to Testing and Adjusting, "Finding Top Center Position for No. 1 Piston". To ensure cylinder No. 1 piston is at top center position compression stroke, both intake and exhaust valves on cylinder No. 1 will move freely. If the intake and exhaust valves do not move freely, cylinder No. 1 is on top center exhaust stroke. Install the timing pin in the flywheel.
Table 1
TDC No. 1 Compression Stroke Inlet Valves Exhaust Valves
Valve Lash 0.38 0.08 mm
(0.015 0.003 inch) 0.64 0.08 mm (0.025 0.003 inch)
Cylinders 1-2-4 1-3-5
Adjust the valve lash according to Table 1.
Lightly tap the rocker arm with a soft mallet. This action will ensure that the lifter roller seats against the base circle of the camshaft.
Loosen the adjustment locknut.
Place the appropriate feeler gauge between rocker arm and the valve bridge. Then, turn the adjustment screw in a clockwise direction. Slide the feeler gauge between the rocker arm and the valve bridge. Continue turning the adjustment screw until a slight drag is felt on the feeler gauge.
Tighten the adjustment locknut to a torque of 30 7 N m ((22 5 lb ft)). Do not allow the adjustment screw to turn while you are tightening the adjustment locknut. Recheck the valve lash after tightening the adjustment locknut. Remove the feeler gauge.
Remove the timing bolt and turn the flywheel by 360 degrees in direction of engine rotation. This will put the No. 6 piston at the top dead center position on the compression stroke. To ensure that cylinder No. 6 is at top dead center compression stroke, both intake and exhaust valves on cylinder No. 6 will move freely. If the intake and exhaust valves do not move freely, cylinder No. 6 is on top center exhaust stroke. Install the timing pin in the flywheel.
Table 2
TDC No. 6 Compression Stroke Inlet Valves Exhaust Valves
Valve Lash 0.38 0.08 mm
(0.015 0.003 inch) 0.64 0.08 mm (0.025 0.003 inch)
Cylinders 3-5-6 2-4-6
Adjust the valve lash according to Table 2.
Lightly tap the rocker arm with a soft mallet. The action will ensure that the lifter roller seats against the base circle of the camshaft.
Loosen the adjustment locknut.
Place the appropriate feeler gauge between rocker arm and the valve bridge. Then, turn the adjustment screw in a clockwise direction. Slide the feeler gauge between the rocker arm and the valve bridge. Continue turning the adjustment screw until a slight drag is felt on the feeler gauge.
Tighten the adjustment locknut to a torque of 30 7 N m ((22 5 lb ft)). Do not allow the adjustment screw to turn while you are tightening the adjustment locknut. Recheck the valve lash after tightening the adjustment locknut. Remove the feeler gauge.
If the engine is equipped with an engine compression brake, follow the procedure down below.
Table 3
TDC No. 6 Compression Stroke
Compression Brake Lash 0.9 0.2 mm (0.035 0.002 inch)
Cylinders 2-4-6
Adjust the compression brake lash according to Table 3.
Install the engine compression brake by referring to Disassembly and Assembly, "Compression Brake Remove and Install".
Begin setting lash on cylinder No. 6 top center compression stroke since engine was on this stroke from setting the engine valve lash.
Turn adjuster clockwise until there is contact with the exhaust valve bridge. Turn adjuster counterclockwise until the adjuster has turned two full rotations or until the rod is not in contact with the exhaust valve bridge ensuring that all the oil has left the cylinder. Install the feeler gauge with adjuster backed out at this time.
Use tooling in order to set brake lash of 0.9 0.2 mm (0.035 0.002 inch). The brake lash is measured