Getting water in outdrive

Hey guys, I have a 1990 thundercraft 1750 SD with the 4.3 liter v6. I have a 1975 "R" outdrive on it due to original vert shaft being broke. The issue I am having is that when I run it on muffs I am getting water in the outdrive. Also it is leaking into the bilge with I believe is a yoke seal issue. Am I right. Thanks in advance for the help.

The issue I am having is that when I run it on muffs I am getting water in the outdrive. Also it is leaking into the bilge with I believe is a yoke seal issue. Am I right. Thanks in advance for the help.

Water entering a drive on muffs can only come from the water pump base. If you mean gear oil leaking into the bilge, then suspect a yoke seal and or the yoke.
When was the drive serviced last?

By the water pump base, do you mean the the metal plate under the pump is leaking or it is just leaking in the lower unit some where.

Yes I meant gear oil is leaking in to the bilge.

The last time it was serviced? Thats a good question. I put a pump in it last year but other than that it has been many years probably 10 plus.

I just purchased the boat last winter for dirt cheap and have slowly been working on it as money allows. I finally have it running and able to test it on the water. Now I am just working out the little bugs. These seem to be the last few bugs so I am getting excited to run it this summer

http://www.boatfix.com/merc/Servmanl/6/6B3R3.PDF
Page 3B-8 #24
upper unit in this link

http://www.boatfix.com/merc/Servmanl/6/6A3R3.PDF

Gotcha, Thanks I will update after I check it out.