Mercruiser 3.0 Motor

Bluefin91

Cadet
Joined
Feb 10, 2018
Messages
23
What year did Mercruiser come out with a 3.0 and would a 1985 block interchange with a 1991.
Thanks for any help.
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
Staff member
Joined
Jul 23, 2011
Messages
50,347
the 3.0 came out in the late 70's

no, the block alone wont interchange with a 1985/1991 1990 was last year for the 2-piece RMS, 1991 and newer were 1-piece RMS (different block)

your not just replacing the block, you are talking complete long-block, or short block, correct. to replace a block requires machining, new bearings, new pistons, rings, etc.

Stick to complete motors, 1990 or older unless you get a complete long-tail
 

Bluefin91

Cadet
Joined
Feb 10, 2018
Messages
23
Thanks, I guy has a 1985 block and flywheel, No head for it , my 1991 has a one piece main, I thought I might be able to use his block and the rest of my parts, looks like it will not work according to your post.
 

Bondo

Moderator
Staff member
Joined
Apr 17, 2002
Messages
71,112
Ayuh,.... You wanta buy a Complete motor, or atleast a Complete Long Block motor,....
Piecin' together a motor outa parts is a false-economy, frustratin' fool's errand,....

A complete runnin' barge, on a wagon, that's Rotten is another viable cheap option too,....
Take what ya need, sell the rest, 'n possibly make money,.....
 
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