Draining And Inspecting Gear Lubricant - Mercury 40 Service Manual

Draining and Inspecting Gear Lubricant

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 re-
move the two vent screws and one fill/drain screw (with gaskets).
a -
b -
c -
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 indi-
cates normal wear. The presence of metal chips on the drain plug bar magnet indicates
the need for gear housing disassembly and component inspection.
3. Note color of gear lubricant. White or cream color MAY indicate presence of water in lu-
bricant. 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 lubricant in gearcase). Gearcase should hold 10 to 12 psi of pressure for 5 min-
utes 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 bottom 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 compo-
nents for damage. If gearcase is rebuilt, gearcase should be pressure checked before
filling with lubricant.
90-828631R3 MARCH 1999
c
Oil Level Screw
Fill/Drain Screw
Vent Screw
WARNING
a
b
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BIGFOOT GEAR HOUSING
Page 6B-11