HD 25 Adding Gear Oil

tj959

Recruit
Joined
May 27, 2009
Messages
5
This may sound stupid but, I drained the oil out of my HD25 lower unit and now I'm having trouble filling it back up. Most engines have an upper and lower plug but this one seems to have just a lower one. Hanging it upside down doesn't seem like a good idea. What am I missing?
 

Gary H NC

Fleet Admiral
Joined
Dec 1, 2005
Messages
8,972
Re: HD 25 Adding Gear Oil

I have never seen one without the vent plug....are you sure its not painted over and you just can't find it?

What year motor is it?
 

tj959

Recruit
Joined
May 27, 2009
Messages
5
Re: HD 25 Adding Gear Oil

This motor was built sometime between 1946 and 1950. I was told it was a 1950. There is a small vent screw further up on the shaft and what looks like a filler screw on the other side but it goes into the exhaust chamber. I suspect that it may be filled from the bottom until it comes out the vent hole. If so, it seems like a poor method to me.
 

tj959

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Joined
May 27, 2009
Messages
5
Re: HD 25 Adding Gear Oil

It was obvious that this lower unit was to be filled from the bottom. I'll have to stop resisting the obvious because it was easy and not half as messy as I expected. Stubborness seems to have been my only problem.
 

wbeaton

Commander
Joined
Jul 30, 2006
Messages
2,332
Re: HD 25 Adding Gear Oil

It was obvious that this lower unit was to be filled from the bottom. I'll have to stop resisting the obvious because it was easy and not half as messy as I expected. Stubborness seems to have been my only problem.

lol. That is the most honest follow up I've read in a long time!

It may seem odd, but it really is a good system. A lower unit oil pump works great for this. If you ever come across an outboard that only has one drain screw the best method is to place it on its side and fill with an oil can.
 
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