Merc Classic 45 Lower unit compatibility

As is evident in a thread I started this AM, I am gonna need a used lower unit for my Merc Classic 45, OB121232.

Trouble is, I don't find any identifying marks on the unit -- is it there somewhere?

What about other motors that used this lower unit? Any help in determining which ones are compatible. FWIW, mine has 11 splines . . .

Re: Merc Classic 45 Lower unit compatibility

Any of the "Classic" variety of 4-cyl 44 C.I. motors would be a good candidate as a donor.

And I'd expect that a number of earlier "500" or "50" 4-cyl models would work as well. Merc didn't make a lot of drastic changes on these great old-design motors. Just refined the Heck out of them up to the last production models.

There are some slight difference in shift shaft designs over the years, but if you were to find a lower unit identical to yours except for shift shaft style, it's not that difficult to change out.

Just make sure you get the appropriate length of driveshaft to fit your motor (likely a Longshaft/fits a 20" transom I'd venture to say).

HTH.........ed