Help changing lower unit oil on 1981 omc 120

[clafever]

This is my first time changing the oil myself. I have the original owner's manual, but some of the pages which instruct on this are missing. My lower unit has an upper and lower gearcase. Should there be two different fill holes or are both filled from the same fill hole on the side? I understand that I have to use a hand pump, which i have, and that the plug on top of the unit must be removed for proper draining to eliminate the vacuum, and then reinstalled while the pump is still attached to hold oil in place. I'm just not sure if everything is filled from the one hole on the side.

 

[southkogs]

I'm assuming we're talking lower unit lube:

The two gear cases are separate in your sterndrive. So, you're working two different fill holes to load up the lower.

The upper gear case you drain though the port (screw head) on the side in this photo:


Fill through the same hole using the hand pump you mentioned.

The lower gear case you drain and fill through two screw head ports - - and I can't believe I don't have a photo showing them!! The vent is just above the cavitation plate on the port/left side of the drive. The fill port is on the lower side of the gear housing "bullet" near the skeg. Again, use your pump to fill it.

Your intermediate housing should have it's lube changed too: That's the screw head at the top of the sterndrive just outside the big rubber seal. You'll need some sort of vacuum pump to suck the lube outta' that one.

Oil change up in the engine, you do pretty much like a car ... except ya' gotta' collect the oil somewhere.

 

[clafever]

Thank you for your very informative reply. I really appreciate it. I think I can get this done based on the info you've given me. I thought there was an intermediate housing that had to be changed too, but was unsure. I have an oil pump that I use to drain the engine oil that I can use to get that oil out. Thanks again!

 

[southkogs]

No sweat ... changing the lube is pretty easy. I'm a pretty much a dope mechanically and I can get it done without injury to myself, the boat or others in a 3 mile radius

 

[superbenk]

The intermediate housing drain is on the starboard side near the ball gear. Remove the fill plug from the top and drain out from the drain plug below. Replace drain plug and fill through the top hole (intermediate only, out drive fill as stated above).