is there any of you duck people on here that would sonsider him/herself a bad arse when it comes to Mercury outboards. Here is me problem. I have a 1999 60HP Mercury Bigfoot 2 stroke engine. The lower unit was no good and in pieces when I got it. It has a vertical shaft with male slines at the top of the shaft where it couples to the power head in a female slined coupler. I would say the top 6 inches of that shaft have been turned down to 5/8 diameter prior to the slines being cut. The rest of the shaft is 7/8s roughly.

I got a new to me but used lower unit from a 4 stroke. There is a 14 day return policy. I didn't realize until yesterday the vertical shaft on it was not turned down to 5/8s. It is straight 7/8s to the end with the splines cut in it.

My question is can I just change shafts? The pinion gear at the bottom on both has 43 44484 part numbers. There is some other numbers but both have that specific number. I am thinking I can just break down the lower unit, exchange the shafts and rock on.

Anyone in here a Mercury wizbang?

Gonna send ya a PM...

Well dang. The rest of us would like to know.

Ha, I don't know a dang thing. I just know somebody that does so I gave him some contact info...

My goodness fella, another project?

Wal has more hobbys and projects than anyone I know.

Larrycopper I called him. He did not know the answer. So when I got home I just said screw it and took the new lower unit all the way to a shell. As my wonderful luck would have it, they are interchangeable, wahooo!!! The only difference between the 4 stroke and 2 stroke is the last upper 4 inches of shaft. I didnt figure they would use the same casing and re- engineer the guts.

Had I not got called out last night I would have bad the whole thing back together and installed on the upper unit.

lol, I was gonna be extremely impressed if LC knew that one.

Alright well we all know the answer now. They are interchangeable. It took about 20 minutes to put it all back together. I am shocked, it works.