Gear Case Lubrication; Draining Gear Case; Checking Lubricant Level And Filling Gear Case - Mercury 30 Service Manual

Gear Case Lubrication

When adding or changing gear case lubricant, visual-
ly check for the presence of water in the lubricant. If
water is present, it may have settled to the bottom
and will drain out prior to the lubricant, or it may be
mixed with the lubricant, giving it a milky colored ap-
pearance. If water is noticed, have the gear case
checked by your dealer. Water in the lubricant may
result in premature bearing failure or, in freezing tem-
peratures, will turn to ice and damage the gear case.
Whenever you remove the fill/drain plug, examine
the magnetic end for metal particles. A small amount
of metal filings or fine metal particles indicates nor-
mal gear wear. An excessive amount of metal filings
or larger particles (chips) may indicate abnormal
gear wear and should be checked by an authorized
dealer.
WARNING
If gear housing is installed on outboard, to avoid
accidental starting, disconnect (and isolate)
spark plug leads from spark plugs before work-
ing 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.

Draining Gear Case

1. Tilt outboard so that lubricant in gear housing will
drain toward front of housing, out fill hole and into
clean container.
IMPORTANT: Inspect FILL and VENT plug wash-
ers for damage. Use new washer as needed.
2. Remove lubricant FILL plug and washer. Note
amount of metal particles on magnetic FILL plug.
Remove all magnetic particles from FILL plug.
3. Remove VENT plug and washer and allow all lu-
bricant to drain.
1B-6 - IMPORTANT INFORMATION
a - Lubricant Vent Plug/Washer
b - Lubricant Fill Plug/Washer
4. Inspect gear lubricant for metal particles (lubri-
cant will have a " metal flake"appearance). Pres-
ence of fine metal particles (resembling powder)
on the FILL plug bar magnet indicates normal
wear. The presence of metal chips on the FILL
plug bar magnet indicates the need for gear
housing disassembly and components inspec-
tion.
5. Note color of gear lubricant. White or cream color
indicates presence of water in lubricant. Gear lu-
bricant which has been drained from a gear hous-
ing recently in operation will have a yellowish col-
or due to lubricant agitation/aeration. This is
normal and should not be confused with the pres-
ence of water.
6. 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.
Checking Lubricant Level and Filling
Gear Case
IMPORTANT: Never add lubricant to gear hous-
ing without first removing VENT plug, as trapped
air will prevent housing from being filled. Fill gear
housing only when outboard is in operating posi-
tion.
a
b
90-826148R2 MARCH 1997