Mariner 100, Service Manual, Page: 201 / 391

5A-32 LOWER UNIT 90-13645--2 1095
Gear Housing Pressure Test
1. Remove vent plug and install pressure test gauge
2. Pressurized housing to 10 to 12 psi 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 wa-
ter.
5. Re-pressurize to 10 to 12 psi and check for air
bubbles.
6. Replace leaking seals as necessary. Retest hous-
ing.
Note: Gearcase should hold 10 to 12 psi for 5 min-
utes.
7. Remove tester from housing and install vent plug.
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
accidental starting, disconnect (and isolate)
spark plug leads from spark plugs before working
near the propeller.
Do not use automotive grease in the gear housing.
Use only Quicksilver Gear Lube or Quicksilver
Super-Duty Lower Unit Lubricant.
CAUTION
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. Remove lubricant “Fill” screw and gasket from
gear housing.
4. Insert lubricant tube into “Fill” hole, then remove
“Vent” screws and gaskets.
5. Fill gear housing with lubricant until excess starts
to flow out of one (first) “Vent” screw hole.
6. Replace this lubricant “Vent” screw and gasket
only and continue filling until excess starts to flow
out of second lubricant “Vent” screw hole.
51552
a
b
c
a - Vent Screw
b - Fill/Drain Screw
c - Oil Level Vent Screw