Mercury Mariner 25HP 4-Stroke Outboard Service Manual 1997, Page 21Get this manual
Timing Belt Inspection 1Inspect the timing belt and replace if any of the
following conditions are found
Lubricate Points thru with Quicksilver 2-4-C Marine Lubricantwith Teflon or Special Lubricant
101 2Swivel BracketLubricate through fitting
aCracks in the back of the belt or in the base of the belt teethbExcessive wear at the roots of the cogs
cRubber portion swollen by oildBelt surfaces roughenedeSigns of wear on edges or outer surfaces of belt
3Tilt TubeLubricate through fittings4Co-Pilot shaft (TIller Handle Models)-Lubricate through fitting Move steering friction lever back and forth while lubricating