Draining And Inspecting Gear Housing Lubricant - Mercury 45 Jet 50-55 Service Manual

2. Place a block of wood, as shown, to prevent pro-
peller from rotating and to protect hands during re-
moval of nut.
3. Remove nut and pull components from shaft.
a - Block of Wood
Draining and Inspecting Gear Housing
Lubricant
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.
1. With gear housing in normal running position,
place a clean pan under housing and remove the
two vent screws and one fill/drain screw (with
gaskets).
90-817643R1 DECEMBER 1996
a
a - Oil Level Screw
b - Fill/Drain Screw
c - Vent Screw
2. Inspect gear lubricant for metal particles (lubricant
will have a "metal flake" appearance). Presence of
fine metal particles (resembling powder) on the
drain plug bar magnet indicates normal wear. The
presence of metal chips on the drain plug bar mag-
net indicates the need for gear housing disassem-
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bly and component inspection.
3. Note color of gear lubricant. White or cream color
MAY indicate presence of water in lubricant. Gear
lubricant which has been drained from a gear case
recently in operation will have a yellowish color
due to lubricant agitation/aeration. Gear lube
which is mixed with assembly lubricant (Special
Lube 101 or 2-4-C w/Teflon will also be creamy
white in color. This is normal and should not be
confused with the presence of water. If water is
suspected to be present in gearcase, a pressure
check of gearcase should be made (with no lubri-
cant in gearcase). Gearcase should hold 10 to 12
psi of pressure for 5 minutes without leaking down.
Pouring a portion of the gear lubricant into a glass
jar and allowing the lubricant to settle will allow any
water in the lube to separate and settle to the bot-
tom of the jar.
4. Presence of water in gear lubricant indicates the
need for disassembly and inspection of oil seals,
seal surfaces, O-rings, water pump gaskets as
well as gear housing components for damage. If
gearcase is rebuilt, gearcase should be pressure
checked before filling with lubricant.
a
c
b
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LOWER UNIT - 6B-9