1992 OMC 3.0 Cracked Block

Scott06

Fleet Admiral
Joined
Apr 20, 2014
Messages
7,524
Is the Mercruiser stuff significantly better? I genuinely have no idea.
really depends so of the early cobras had teething issues and gave the brand a bad name. Biggest issue is parts and service availability. the transom keyhole is the same so if you have the complete merc pulleys to prop I would consider it. 1993 is the alpha gen 2 drive which is current as still sold new.

If you can get parts for the OMC still its less work to just swap the long block, but Im not sure I would spend the money on a manifold for a obsolete set up.
 

Jcgonzal

Cadet
Joined
Jul 21, 2026
Messages
10
My only concern is that this boat was having fuel delivery issues, and I just spent $400 getting my OMC (Holley) carb professionally rebuilt; can I use Mercruiser outdrive/controls and OMC manifold? If nothing else I’ll pull everything from the donor boat and can switch things out later…
 

Scott06

Fleet Admiral
Joined
Apr 20, 2014
Messages
7,524
My only concern is that this boat was having fuel delivery issues, and I just spent $400 getting my OMC (Holley) carb professionally rebuilt; can I use Mercruiser outdrive/controls and OMC manifold? If nothing else I’ll pull everything from the donor boat and can switch things out later…
Hard to say with out the parts in front of you. Def more work to change it over- if you already have the carb redone just swap the long blocks then.

Did you clean the fuel tank and replace the lines? highly likely due to age there is some contamination and you dont want to pollute the carb with the same chit that mucked it up in the first place.
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
Staff member
Joined
Jul 23, 2011
Messages
52,867
the merc manifold must mate up to a merc transom shield. the Obsolete Marine Corp manifold must mate up to an OMC transom shield.

you can get parts for the mercruiser. OMC has been out of business nearly 30 years.

from a work stand-point. you can be boating as early as late this afternoon by simply swapping the whole mercruiser setup into your boat
 
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