49838 Mercruiser NUT, EXHAUST MANIFOLD STUD

Table 1
Required Tools
Tool Part Number Part Description Qty
A(1) 9U-6198 Crankshaft Turning Tool 1
A(2) 9U-7336 Housing 1
5P-7305 Engine Turning Tool 1
B 367-8608 Engine Timing Pin 1
C 370-4657 Rocker Arm Spacer 6
(1) The Crankshaft Turning Tool is used on the front pulley.
(2) This Tool is used in the aperture for the electric starting motor.Start By:
Remove the valve mechanism cover. Note: Either Tooling (A) can be used. Use the Tooling that is most suitable.
Keep all parts clean from contaminants.Contaminants may cause rapid wear and shortened component life.
Illustration 1 g01992076
Remove plug (2) from the cylinder block. Remove O-ring seal (1) from the plug.
Use Tooling (A) to rotate the crankshaft so that number one piston is at top dead center on the compression stroke. Refer to System Operation, Testing and Adjusting, "Position the Valve Mechanism Before Maintenance Procedures" for the correct procedure. Install Tooling (B) through Hole (W) in order to lock the crankshaft.
Remove Tooling (B).
Use Tooling (A) to rotate the crankshaft in a clockwise direction and position the crankshaft at 60 degrees after top dead center.
Illustration 2 g01992077
Loosen threaded inserts (4) on all rocker arms (3). Unscrew threaded inserts (4) on all rocker arms (3) until all valves are fully closed. Ensure that guides (5) for the pushrods are left in position on threaded inserts (4). Note: Ensure that ALL threaded inserts are fully unscrewed.
Illustration 3 g02003036
Illustration 4 g02003035
Loosen Torx screws (7). Begin at the ends of rocker shaft assembly (2) and work toward the center. Note: To avoid distortion of the rocker shaft assembly, each Torx screw should be loosened by half a turn at one time. Repeat the procedure until all Torx screws are loosened.
Remove Torx screws (7) from rocker shaft assembly (8). Note: Note Position (X) of different length Torx screws (7).
Remove rocker shaft assembly (8) from the cylinder head.
Place an identification mark on pushrods (9) to show the location. Remove the pushrods from the cylinder head. Note: Identification will ensure that the pushrods can be reinstalled in the original positions. Do not interchange the positions of used pushrods.
Make a temporary mark on valve bridges (6) to show the location and the orientation. Remove the valve bridges from the cylinder head. Note: Identification will ensure that the valve bridges can be reinstalled in the original location and the original orientation. Do not interchange the location or the orientation of used valve bridges.Installation Procedure
Note: Either Tooling (A) can be used. Use the Tooling that is most suitable.
Illustration 5 g02004077
The correct location of valve bridges on valve stems is shown.
Clean valve bridges (6). Inspect the valve bridges for wear and damage. Replace any valve bridges that are worn or damaged.
Lubricate valve bridges (6) with clean engine oil.
Failure to ensure that ALL valve bridges are correctly seated onto the valve stems will cause interference between the pistons and the valves, resulting in damage to the engine.
Install valve bridges (6) to the valve stems. Note: Install used valve bridges in the original location and in the original orientation. Ensure that the valve bridges are correctly seated on the valves. New valve bridges may be installed in either orientation.
Illustration 6 g02004093
Clean the pushrods. Inspect the pushrods for wear and damage. Replace any pushrods that are worn or damaged.
Apply clean engine lubricating oil to both ends of pushrods (9). Install the pushrods to the engine with the cup upward. Note: Ensure