879900 Mercury NUT, (52 mm)

Table 1
Required Tools
Tool Part Number Part Description Qty
A 230-6284 Timing Pin (Camshaft) 1
B 136-4632 Timing Pin (Crankshaft) 1
268-1966 Adapter 1
Keep all parts clean from contaminants.Contaminants may cause rapid wear and shortened component life.
Ensure that number one piston is at top dead center on the compression stroke. Refer to System Operation, Testing and Adjusting, "Finding Top Center for No. 1 Piston" for the correct procedure.
Illustration 1 g01337918
Alignment of timing marks
Ensure that Tooling (A) is installed into Hole (X) in camshaft gear (1).
Illustration 2 g01337947
Ensure that Tooling (B) is installed in Hole (Y) in the cylinder block. Use Tooling (B) in order to lock the crankshaft in the correct position. Refer to System Operation, Testing and Adjusting, "Finding Top Center Position for No.1 Piston" for the correct procedure.
Illustration 3 g01337949
Clean idler gear (2) and inspect the idler gear for wear or damage. Refer to Specifications, "Gear Group (Front)" for more information. If necessary, replace the idler gear.
Clean hub (7) and inspect the hub for wear or damage. Refer to Specifications, "Gear Group (Front)" for more information. If necessary, replace the hub.
Lubricate hub (7) with clean engine oil. Slide hub (7) into idler gear (2). Ensure that the timing marks are toward the front of the idler gear.
Illustration 4 g01337952
Align the timing mark on idler gear (2) with the timing mark on the camshaft gear. Refer to the illustration 1. Install the assembly of idler gear (2) and hub (7) into the recess in the timing case. Ensure that oil Hole (Z) is to the top of the hub. Note: The idler gear must be tilted during installation. Ensure that the holes in the hub are aligned with the holes in the cylinder block.
Clean plate (3) and inspect the plate for wear or damage. If necessary, replace the plate.
Lubricate plate (3) with clean engine oil. Align the holes in plate (3) with the holes in hub (7). Install the plate in the original orientation.
Install bolts (1).
Remove Tooling (A) and Tooling (B). Note: Ensure that timing marks are aligned, before removing the Tooling (A) and Tooling (B).
Install plug (8) to the cylinder block. Refer to Illustration 2.
Tighten bolts (1) to a torque of 44 N m (32 lb ft).
Illustration 5 g01337953
Checking end play by using a set of feeler gauge's
Use a set of feeler gauge's in order to check the end play for the idler gear. Refer to Specifications, "Gear Group (Front)" for more information.
Illustration 6 g01335426
Checking backlash
Check the backlash between the idler gear and the camshaft gear. Refer to Specifications, "Gear Group (Front)" for more information.
Check the backlash between the idler gear and the crankshaft gear. Refer to Specifications, "Gear Group (Front)" for more information.
Lightly lubricate all of the gears with clean engine oil. End By:
Install the fuel injection pump gear. Refer to Disassembly and Assembly, "Fuel Pump Gear - Install" for the correct procedure. Installation Procedure (Early Heavy-Duty Idler Gear)
Table 2
Required Tools
Tool Part Number Part Description Qty
A 230-6284 Timing Pin (Camshaft) 1
B 136-4632 Timing Pin (Crankshaft) 1
268-1966 Adapter 1
C 9U-7324 Indicator Bracket 1
7H-1942 Dial Indicator 1
3S-3268 Indicator Contact Point 1