Mercury Mariner 25HP 4-Stroke Outboard Service Manual 1997, Page 24Get this manual
Gear Case Lubrication When adding orchanging gear case lubricant, visually check for the presence of water in the lubricantIf 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 milky colored appearanceIf water is noticedhave the gear case 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 gear caseWhenever you remove the filldrain plug, examine the magnetic end for metal particlesA small amount of metal fi lings or fine metal particles indicates no(mal gear wearAn excessive amount of metal filings or larger particles (chips) may indicate abnormal gear wear and should be checked by an authorized dealer
Checking Gear Case Lubricant Level and Refilling Gear Case