Checking Timing Chain Deflection - Mercury MerCruiser Service Manual

Engine Inspection and Assembly
6. Install the camshaft sprocket and timing chain. Tighten the sprocket screws to the specified torque.
b
a
Description
Camshaft sprocket screws

Checking Timing Chain Deflection

1. Rotate the camshaft (in either direction) to place tension on one side of the chain.
2. Establish and mark a reference point on the block (on taut side of chain) and measure from this point to the chain.
3. Rotate the camshaft in the opposite direction to provide slack in the chain.
4. Push the chain in toward the sprockets and measure the distance between the reference point and timing chain.
5. The deflection is the difference between these two measurements. If the deflection exceeds specification, the timing chain
should be replaced.
Description
Chain deflection
Page 3B-36
c
Measuring timing chain deflection
© 2016 Mercury Marine
a - Crankshaft sprocket
b - Camshaft sprocket
c - Timing marks
59477
Nm
25
59549
11 mm (0.4331 in.) maximum
90-8M0099748 eng DECEMBER 2015
lb‑in. lb‑ft
– 18.4
6.2 Liter