Gearcase Lubrication; Draining Gearcase; Gearcase Lubricant Capacity; Gearcase Lubricant Recommendation - Mercury 25 EFI Service Manual

Maintenance
9. Align the propeller nut with the propeller shaft hole. Insert a new cotter pin in the hole and bend the cotter pin ends.
Description
Propeller nut
10. Install the spark plug leads.

Gearcase Lubrication

When adding or changing gearcase lubricant, visually 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
appearance. If water is noticed, have the gearcase checked by your dealer. Water in the lubricant may result in premature
bearing failure or, in freezing temperatures, will turn to ice and damage the gearcase.
Examine the drained gearcase lubricant for metal particles. A small amount of metal particles indicates normal 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.

Draining Gearcase

1. Place outboard in a vertical operating position.
2. Place drain pan below outboard.
3. Remove vent plug and fill/drain plug and drain lubricant.

Gearcase Lubricant Capacity

Gearcase lubricant capacity is approximately 350 ml (11.8 fl. oz.).

Gearcase Lubricant Recommendation

Mercury or Quicksilver Premium or High Performance Gear Lubricant.

Checking Lubricant Level and Refilling Gearcase

1. Place outboard in a vertical operating position.
2. Remove vent plug.
Page 1B-12
28353
a
b
9836
© 2016 Mercury Marine
28351
a - Vent plug
b - Fill/drain plug
Nm lb‑in.
25 –
90-8M0105568 eng MARCH 2016
lb‑ft
18