Mercury 100 FourStroke, Service Manual

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90-830234R3 DECEMBER 1997 LOWER UNIT - 6A-33
Gear Housing Pressure Test
1. Remove vent plug and install pressure test
gauge.
2. Pressurized housing to 10 to 12 psi (68-82kPa)
and observe gauge for 5 minutes.
3. Rotate drive shaft, prop shaft and move shift
shaft while housing is pressurized to check for
leaks.
4. If pressure drop is noted, immerse housing in
water.
5. Re-pressurize to 10 to 12 psi (68-82kPa) and
check for air bubbles.
6. Replace leaking seals as necessary. Retest
housing.
NOTE: Gearcase should hold 10 to 12 psi (68-82
kPa) for 5 minutes.
7. Remove tester from housing and install vent
plug. Torque vent screw to 60 lb. in. (6.8 N·m).
Filling Gear Housing With
Lubricant
NOTE: Gear housing lubricant capacity is 22.5 fl. oz.
(665.2ml).
WARNING
If gear housing is installed on engine, to avoid ac-
cidental starting, disconnect (and isolate) spark
plug leads from spark plugs before working near
the propeller.
CAUTION
Do not use automotive grease in the gear hous-
ing. Use only Quicksilver Gear Lube or Quicksil-
ver Super-Duty Lower Unit Lubricant.
1. Remove any gasket material from “Fill” and
“Vent” screws and gear housing.
2. Install new gaskets on “Fill” and “Vent” screws.
IMPORTANT: Never apply lubricant to gear hous-
ing without first removing “Vent” screws or gear
housing cannot be filled because of trapped air.
Fill gear housing only when housing is in a verti-
cal position.
3. Insert lubricant tube into “Fill” hole.
4. Fill gear housing with lubricant until excess starts
to flow out of one (first) “Vent” screw hole.