Mercruiser 120 Rebuild.....Bad news

[Ragan2009]

1966 Mercruiser 120. Finally got it to fire up after 24 years of just sitting and then noticed a water leak under the Exhaust manifold. Took the Manifold off and noticed a hairline cracked block(Pictures Below). Is this repairable or am I just wasting my time on restoring this 1966 Starcraft? Is it worth buying another block? I was really wanting to restore this boat since it has been in the family for 45 years.

 

[fat fanny]

Re: Mercruiser 120 Rebuild.....Bad news

That's a bit more than a hair line crack! real close to the deck to if it's that sentimental to keep talk to a engine shop for thier recomendation could be costly and will most likely suggest long block.

 

[Alpheus]

Re: Mercruiser 120 Rebuild.....Bad news

PM Sent

 

[Don S]

Re: Mercruiser 120 Rebuild.....Bad news

That is a very typical crack caused by freezing. Some have attempted to patch with epoxy, but the big problem is if the crack is also internal and puts water into the engines crankcase. that can't be fixed.

 

[Ragan2009]

Re: Mercruiser 120 Rebuild.....Bad news

That is a very typical crack caused by freezing. Some have attempted to patch with epoxy, but the big problem is if the crack is also internal and puts water into the engines crankcase. that can't be fixed.

Don S., Is the best thing to upgrade engine? Or get another block and rebuild? It was a real bummer to finally get this 44 year old motor running again then notice the water leak (I was hoping it was the manifold gasket) then pulled the manifold to notice this crack in the block. The boat is 1966 Starcraft 18 footer. Could be really cool if fully restored. I am thinking of just trying to find another block or engine on ebay or something like that. What do you think?

 

[Bondo]

Re: Mercruiser 120 Rebuild.....Bad news

Ayuh,... I'd think it Might be worth a tube of epoxy, just to find out if it's cracked, Internally,...

I was really wanting to restore this boat since it has been in the family for 45 years.

So longs the Hull is Ok,...
You could drop in Brand New power if ya Want too....
Motor, transom, 'n drive....

 

[Don S]

Re: Mercruiser 120 Rebuild.....Bad news

Being a 66, you are back at least a year before the MC 1 drive came out. Those old EZ shift models have a lot of NLA (No longer available) parts. If you want to keep the boat, and the boat is in good shape, perhaps a complete NEW repower would be the way to go, it's your wallet, not mine. Here is an example http://www.marinepowerservice.com/BoatingStore/browse_detail3.cfm/productID/23391.cfm

Or you may be able to find an old dead boat with a good, newer (mid 80's or newer) 3.0L engine and drive and just swap it over.
At least you would have a useable boat with a drive system you can get parts for.

 

[grzzzz]

Re: Mercruiser 120 Rebuild.....Bad news

I had the same problem with the $600, 66 I bought. But for $600 I assumed the motor was bad. I completely rebuilt mine, bored/pistons, Re-cut valves, increased size/sets, new cam, etc. ... The blocks are out there. BUT, be careful where you get it. I shipped 2 in before I got a good one I could work with. Shipping $s down the drain. Seems the last year someone uses the boat they don't bother doing a proper winterization. A lot of bad blocks out there. I have a spare motor in my parts boat but not willing to part with it yet. Look around in the Detroit/metro area. With the economy the way it is there you can pick up a whole boat that around that year for a few $100. Problem is they typically don't bother advertising them if they are ... giving them away. Might just goolgle marinas in they area. There are a couple boat junk yards there too.

Grzzzz

 

[dn010]

Re: Mercruiser 120 Rebuild.....Bad news

I've got a whole engine with a good block being .30 over, but it is all apart. Too bad your in SC!

 

[iSteelHead]

Re: Mercruiser 120 Rebuild.....Bad news

I found a New block for my 1972 120hp Merc for about $300 locally. They very simple to work on, if you decide to rebuild. Though I would Try some JB Weld, couldn't hurt. Also it is a lot nicer on the wallet, give it a try!

 

[Ragan2009]

Re: Mercruiser 120 Rebuild.....Bad news

I found a New block for my 1972 120hp Merc for about $300 locally. They very simple to work on, if you decide to rebuild. Though I would Try some JB Weld, couldn't hurt. Also it is a lot nicer on the wallet, give it a try!

Thanks for all the info. I am going to try the weld first, and see what happens.