Timing Belt Removal And Installation; Timing Belt Removal - Mercury 25 EFI Service Manual

Timing Belt Removal and Installation

Timing Belt Removal

IMPORTANT: This engine utilizes an interference valve train design. Do not rotate the crankshaft or cams when the timing belt
is removed from the cam gears or crankshaft gear unless advised to do so. Failure to adhere to this caution may result in valve
and or piston damage.
IMPORTANT: If the timing belt slipped or broke apart while the engine was running, the engine must be disassembled and
inspected for damage.
1. Remove the timing belt cover and recoil assembly. Refer to Section 8 ‑ Manual Starter.
2. Remove the stator assembly. Refer to Section 2A ‑ Stator Removal and Installation.
3. Remove the three bolts securing the stator/crank position sensor (CPS) mounting plate to the engine.
NOTE: It is not necessary to remove the crank position sensors from the stator/CPS mounting plate when replacing the
timing belt.
4. Remove the bolts securing the lifting bracket to the cylinder block.
a
5. Ensure the crankshaft timing mark (flywheel key way) and the cam gear timing mark are in proper alignment. If the timing
marks are out of alignment, install the flywheel onto the crankshaft or use the crankshaft holding tool and rotate the engine
so the # 1 timing mark on the cam gear is properly aligned with the mark on the cylinder head. Check for proper alignment
of the crankshaft timing mark.
a
Crankshaft Holding Tool
6. Remove the timing belt tensioner bolt.
90-8M0105568 eng MARCH 2016
b
c
b
Timing, Synchronizing and Adjustments
a - Bolts securing stator/CPS mounting plate
b - CPS
c - Bolts securing lifting bracket
9931
c
d
91‑898101360
© 2016 Mercury Marine
a - Crankshaft flywheel key
b - Cylinder block timing
mark
c - Cylinder head timing
mark
d - Cam gear timing mark
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