Powerhead Disassembly - Mercury 75 Service Manual

Powerhead Disassembly

Remove fuel pump by removing 2 screws.
Remove oil injection pump by removing 2 bolts.
Remove hoses to fuel pump and oil injection
pump.
b
a - Bolts – Fuel Pump
b - Bolts – Oil Pump
Remove oil injection pump shaft and housing.
a
a - Pump Housing
b - Pump Shaft
4 Cylinder Models Only – Remove accelerator
pump hoses from #3 and #4 cylinder check valve
fittings.
90-830234R3 DECEMBER 1997
a
a
53992
b
20041
Remove check valves.
a
a - Check Valve (4 Cylinder Models Only)
Accelerator check valves can be tested for prop-
er performance as follows:
1. Spray a small amount of WD-40 into barbed end
of check valve.
2. Blow out excess WD-40 with high pressure air.
3. Apply suction to barbed end with small air vacu-
um hand pump.
4. Apply suction until valve opens (22-28 inches of
vacuum).
5. Within 30 seconds after stopping suction, vacu-
um should not fall below 5.0 hg.
NOTE: Accelerator check valves should not be
installed in block while honing operations are being
performed nor reinstalled until all block cleaning pro-
cedures have been completed.
52478
POWERHEAD - 4-35