1992 OMC 3.0 Cracked Block

[Jcgonzal]

New member here, just bought my first boat. I knew it was going to be a project, but didn’t anticipate this. Long story short the previous owner left the boat docked overnight and somehow took on water; he took off the fuel pump and water separator looking for water in the fuel system but didn’t find any. He then moved and lost those two parts.

Fast forward about two years of sitting and I buy the boat. I put a brand new fuel pump and water separator on, also get the carb professionally rebuilt because it was beyond crusty. I get the boat started on the hose for the first time and immediately get water leaking out of the manifold side of the engine…was hoping it was just a cracked manifold. Took the manifold off tonight and found a sizable crack in the block directly below the exhaust ports. I also checked the oil and it was a milkshake, looked clean before I ran it. I’m very green when it comes to boat motors, so I guess my question is: what are my options? Would this crack allow water into the oil, or would that have to be manifold/head gasket related? I’m more than deflated, was really hoping to get the family out on the water this summer….I appreciate any and all insight.

View attachment IMG_2207.mov

 

[racerone]

Block needs to be replaced.----Typical damage from coolant freezing.

 

[Scott Danforth]

first, welcome aboard

that block went thru a freeze. the block is busted on the outside where you see it, and on the inside, just above the pan rail

the rusty goo in the upper right of the corner says your manifold was also freeze busted.

you need a new motor.

since it sat with water in the oil, none of it is salvageable except hardware.

any 1991 to 2015 3.0 will bolt right in. for the base motor you can get a used one from any source as they all came from GM

a reman'd motor from michigan motorz will be $4100, a new one is about $5700

you will need OMC specific manifold.

you can unbolt all the OMC stuff and bolt in a complete 1992 or later Mercruiser 3.0 and Alpha drive should you go looking for a complete bobtail.

what is the condition of the transom and stringers in your 36 year old boat?

 

[Jcgonzal]

first, welcome aboard

that block went thru a freeze. the block is busted on the outside where you see it, and on the inside, just above the pan rail

the rusty goo in the upper right of the corner says your manifold was also freeze busted.

you need a new motor.

since it sat with water in the oil, none of it is salvageable except hardware.

any 1991 to 2015 3.0 will bolt right in. for the base motor you can get a used one from any source as they all came from GM

a reman'd motor from michigan motorz will be $4100, a new one is about $5700

you will need OMC specific manifold.

you can unbolt all the OMC stuff and bolt in a complete 1992 or later Mercruiser 3.0 and Alpha drive should you go looking for a complete bobtail.

what is the condition of the transom and stringers in your 36 year old boat?

Awesome information, thank you! The transom, floor and seats seem to be in great shape, which is the only reason I’m considering replacing the engine. I only have about $1200 invested so far; obviously new or reman would far exceed the value, so I’m hoping to find used.

 

[Bondo]

Awesome information, thank you! The transom, floor and seats seem to be in great shape, which is the only reason I’m considering replacing the engine. I only have about $1200 invested so far; obviously new or reman would far exceed the value, so I’m hoping to find used.

Ayuh,...... Welcome Aboard,...... Are you going to do it, or hire it out,..??

 

[Jcgonzal]

Ayuh,...... Welcome Aboard,...... Are you going to do it, or hire it out,..??

I’m relatively mechanically inclined…never done a motor swap (other than one motorcycle) so I’m hoping to do it myself, if I can find a good deal on a motor!