TOPIC: New seal for the Lower

My Lower leaks and I want to reseal over the winter break. Oil trickles out if left standing upright, and last I changed the oil there was water in it.

Note that I am on the look out for a new lower as mine has a broken fin, a crack repair on the bullet at the prop end, and a chipped flange where it meets the Mid. All that said, I don't have alot of cash for a replacement lower (at least based on the prices I have seen on flea-bay), and this one shifts fine and looks fine (save the shortened fin)

How hard is it? Do I need special tools?

Peter,
No special tools required & only a '1 hammer' level of difficulty.
I may have a good lower unit assembly to sell you if someone closer doesn't have one.
Often, the oily ooze found dripping from the lower unit is just fuel mix and carbon goo wicking its way down the exhaust and out the prop-shaft opening, but given that you have found water in the gear oil it does sound like it needs to be re-sealed.
This is a typical failure on the older lower units because they have a steel driveshaft & propshaft. Consequently water stands and rust forms at the seal positions, causing the seals to leak.
Unless you find fishing line spooled around the prop shaft and propshaft seals area, the most common failures are the driveshaft surface and related seals found under the base of the water pump housing, and the shift shaft's seal surface and related shift shaft seal. These can be R&R'd without much dis-assembly, but to R&R the prop shaft's seal surface if found to be at fault will require extreme disassebly. A (4) hammer job at minimum.
If your gear case was in better condition, I would recommend pressure testing it and simply re-sealing it or at the most a full disassembly to re-seal and install speedi-sleeves to the seal surfaces & re-assemble.
Full disassembly does call for a couple of special tools.
If you want to go to this length - you could get all those broken & missing pieces replaced by an aluminum welding shop.
I can supply the pieces needed to use in these areas so that the shape will be correct. I would simply cut off over-sized pieces based on a few pictures, and you could cut them down to fit before handing it off to the welder.
Or - like you said,...Replace the unit.
I have attached a picture explaining how to remove the lower unit.
Thom

Here's a few pics of the lower unit - all the "issues" are really not important, with the exception of course of the leak

Oh, and here is the progress on painting her up. Hope to paint the Mid today with color coats. I've decided to add two coats of Merc Clear Coat as I've noticed the phantom black scuffs easy.

Peter,
Wow!!!,...You're really going after it!
Are you going to add the late '80s integral PT?
I could send you pieces to match those broken areas, but personally,...I'm really hesitant to spend any money on a gear case that has the exhaust area cracked so badly.
It is quite difficult to get that crack closed back up properly so the retaining ring's threads align and the diameter is correct so that the retaining ring won't strip or jump its threads when tightening it. Granted,...If the crack doesn't go forward into the gear oil area, you can compress that crack enough to assemble and thread the retaining ring in snuggly, but not super tight, and then drill and pin the retaining ring in a few places around the bullet, but that's not very classy - like your Merc and Thompson are.

Thom

Peter good luck with the lower but you really should consider spending some time finding a replacement.... I have found then really cheaply with some patience and research.

Thom...THANKS so much for that great tip on using the washers to break the lower. I consider myself a pretty resourceful guy and have worked myself thru a great many issues with older motors and that is one more tool for my tool-box.

Tnanks,

Tim

Yeah not going to put anything into this lower other than painting it up to match the rest. I'll check the pump and other seals to help. I'll keep the oil changed and watch for a good lower at a fair price.

Oh, and Thom, you bet I'll be using that 80's IPTT.....

was the inline 4 and inline 6 internal pump trim set up different from each other?

Im guessing a 500 merc's internal ram set up is different than a late 1150.?
Conrad