'89 115 lower unit fluid

[alperovich]

hey guys, i would like get some info on changing the fluid in the lower unit.

I have already located the oil level, and drain plugs, and have drained the nasty chocolate milk that was in there :/ hoping its not mixing with water.

What i'm wondering about is, what fluid should i use/how much of it, and what's the best practice for filling, i've been reading something about having to pump it from the bottom?

thank for the help!

[99yam40]

Any good marine grade lower unit lube should be fine and yes it is filled py pushing into the drain until it comes out the vent.

A service manual will help you on any maintenance you do your self.

Chocolatemilk looking lube is indicating water, pressure test lower unit and repair before refilling

[alperovich]

any link to how to do a pressure test?

also any idea how much fluid i'm gonna need? I'll probably have to run to west marine and pick up a pump kit

[coueytwo]

wal mart and K-Mart both sell the pumps with the Yamaha adapt with the oil.
would check the prices out on line first and then buy.
screw hose into lower hole, pump until oil comes out of top plug. replace top screw in top hole. remove hose from bottom hole, very quickly replace the bottom screw. remove top screw for 10 Min's, (to air escape) replace top screw.... your done.

[Aquasportfisher]

If the old gear lube looked like chocolate milk, there's water getting in somewhere. A pressure test will find the leak. With the LU off the motor, use the hose off the gear lube pump attached to the top plug and simply blow on the tube. This will quickly find the leak- more rhan likely a driveshaft seal or the shift shaft seal. You want to find the leak before refilling.