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Mercruiser engine swap

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Listerofsmeg

New member
Hi guys
I have an 84ish Mercruiser 3.0 I4 with a cracked block.
Im not trying to do anything clever, just switch out the entire engine. I have a chance to buy an 87 which looks identical, but theres another that is a 92 I like more.

I've read that in 1992 alot of changes happened and a direct swap out wont be possible? Should I just stay in the 1980s to be sure?
I have an Alpha one gen 1 out drive

Appreciate the help
 
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Ayuh,.... If the motors are Complete, Drop-in ready,...

Any of 'em will drop right in,....

If ya gotta strip parts off one to put another in,... Ya wanta stay Pre-1990,....

In 1990, the rear main seal changed, the crankshaft, 'n it's bolt pattern,.... 2 pc. to 1 pc....
 
yep not planning on anything fancy, no parts swap just drop in and shove the outdrive into it.
(obviously after a correct alignment)
So thats very good news thanks! I really would rather have the 92 as its just had a carb job and new starter!
Thanks!
 
One of the beauties of GM Chevy case engines is that all the bell housing bolt patterns to the rear of the block interchange.
I've direct swapped a white case Mercruiser with a 60's era 4 cylinder, to a mid 70's engine, then updated to late 70's
black Mercruiser outdrive with hydraulics. Then recently a 92, GM V-6 outdrive & bell housing onto the 70's era 4 cylinder.
The guy I got the '92 stuff from had just swapped a blown GM V-6 for a Chevy V-8 in his boat with a Mercruiser.

There's several differences in the engines, the rear transom mount and bell housings need to be a matched pair, but the different GM engines
will bolt up to any of them.
 
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Thats good to know thanks, because I need to move my coupler over from my old engine.
Also hoping the fuel pump from my 84 will work on my 92

Also missing the splash guard for the flywheel but I dont think thats a biggy
 
I would consider the fuel pump a wear item and replace it, not use one that old.... Besides... there may be ethanol issues with the circa 84 pump diaphragm... I don't like spending $$$ any more than the other guy, HOWEVER... reusing a 1984 fuel pump not the way to save money ( unless that "84" fuel pump itself is "new")
 
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Yeah I agree I was just trying to get this engine running with water through it to test the block and head before throwing more money into it.
Once I know its good, ill be buying a new fuel pump, fuel line and engine coupler for sure.
 
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