Located above the water pump impeller on many two stroke and
four stroke models, 115 hp~250 hp, there are two wave washers
and a flat washer underneath a plastic spacer and metal retaining
collar. These components minimize driveshaft movement, up and
down, to quiet the knock sometimes heard at low speeds. They
must be removed anytime the water pump impeller is removed for
service procedures.
Removing the metal retaining collar, though, can be a challenge.
Place a used water pump cartridge (or use the previous one ) over
the impeller.The cup provides fulcrum points 360˚ around driveshaft.
You can now place a pair of straight blade screwdrivers under the lip
of the metal retainer, 180˚ apart, to slowly pry with both, walking
the retainer up the shaft until free. Try it! This works a lot better than
methods I have previously used.
Remember, when reinstalling the washers, collar, and retainer, lift
up on the driveshaft while pressing the retainer over the collar.
Three hands make this part of the process easier but since most of
us only have two, a close fitting section of pipe or tubing
(7/8″ [22mm] ID) can be used to lightly tap it into place. Or what
I prefer is an open-end or adjustable wrench will also work well.
Portions of this article are republished from the Yamaha On Board Magazine with full permission from Yamaha Motor Corp USA
Some of these comments and suggestions are from SIM Yamaha and do not reflect, nor are they intended to represent, any position from Yamaha Motor Corp USA. SIM Yamaha freely offers this advice based on our years of experience selling Yamaha outboard engines, replacement parts and servicing Yamaha outboards. Our primary goal is to give you the information you need to properly maintain your Yamaha outboard engine.