Mercruiser outdrive identification

Pikey23

Petty Officer 3rd Class
Joined
May 31, 2010
Messages
93
My wife and I bought a 1984 fourwinns this year with a 3.0L 140 mercruiser, I can not identify what drive is in it though. I pulled the drive today after winterizing the boat so I could check the gimball bearing and u-joints. I have been told that it is a pre-alpha, a alpha 1 gen 1, and a MR. I really have no idea and would like to get some parts. The number stamped on the upper unit is A422131 the transom assembly serial number is A406605. Any help would be great. Thanks
 

Bifflefan

Commander
Joined
May 27, 2009
Messages
2,933
Re: Mercruiser outdrive identification

I have been told that it is a pre-alpha, a alpha 1 gen 1, and a MR
That is correct. They are one and the same.
There is not really and A1 gen1 per say, but if its the original one its an MR.
83 was an R and 85 is an actual alpha 1.
 

Pikey23

Petty Officer 3rd Class
Joined
May 31, 2010
Messages
93
Re: Mercruiser outdrive identification

So do the MR and A1 basically use the same parts? I need u-joints and a gasket kit to remount.
 

thumpar

Admiral
Joined
Jun 21, 2007
Messages
6,138
Re: Mercruiser outdrive identification

I would change the impeller also unless you know for sure it was changed in the last 2 years.
 

Bifflefan

Commander
Joined
May 27, 2009
Messages
2,933
Re: Mercruiser outdrive identification

Check out this link.

I just reread the history and I made a mistake. 83 and 84 are "R" drives 85 is a "MR" and 86 on is Alpha 1.
"R" meaning Redesign
"MR" meaning Mercruiser Redesign
 

Bondo

Moderator
Staff member
Joined
Apr 17, 2002
Messages
71,082
Re: Mercruiser outdrive identification

So do the MR and A1 basically use the same parts? I need u-joints and a gasket kit to remount.

Ayuh,... That is Correct...
 
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