1973 Mercury 20 hp and lower unit oil

[kevman]

As stated I have a 20 hp Mercury and I recently changed my lower unit oil. The first time I did it, I put oil in the top vent hole and it came out by the prop. So I thought I had bad prop shaft seals. I took it apart an looked it over and everything seemed to be in very good condition. I put it all back together and a friend helped me put in the new oil. He showed me how to put it in the correct way from the bottom. This time nothing came from the bottom of the prop. We filled it until oil came from the small screw hole next to the upper vent screw. We made sure there were no more air bubbles. My question is:

Should I have kept filling until it came out the top vent hole or was it full when it came out of the smaller hole? I am sure by now anyone who reads this will know that I know little about these outboards. Any advice or input is welcome.

Thanks,

Kevin

 

[Mi duckdown]

Re: 1973 Mercury 20 hp and lower unit oil

That is the proper way to fill it, Bottom to top. did you install New washers?
I would do a pressure and vacuum check on that lowerend, to make sure everything is OK.
At the least.