View Full Version : Help with 1977 mercruiser 140hp 4 cylinder inboard
"Just purchased a 1977 crestliner with a 140hp inboard 4 cylinder mercruiser motor. I was told that it had a cracked head. Took the head off yesterday, and discovered that the block was cracked too. I'm at a loss as to how to get a block for this motor. Would a regular GM 4 cylinder block work or does it have to be a special type. I was also thinking that I could transfer all the "goodies" inside the motor, as long as they were in good shape into the new block. I'm leary of taking it to a boat shop, especially since the nearest one is an hour away.
I would appreciate any advice that anyone could give me on this. (I only paid $400 for the boat and trailer, so I don't want to shell out $2,000 for a motor).
If you want to look at the pictures at the boat (ignore the other photos. The last 3 photos show the crackin the block.), you can go to
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04-03-2006, 10:15 PM
"Either monitor EBay or check out Jasper Engines, they are a national rebuilder and may be the most economical way to go."
04-03-2006, 10:34 PM
"That's a marine only motor, not a standard GM 4 banger. You'll need a rebuilt or good used long block. Sorry.
04-05-2006, 08:11 PM
"OMG, What a time machine! What a bargain for the dollars spent. I hope you find an economical solution to the engine probs so you get out on the water for a bit of fun. Don't forget the Johnny Cash cassette."
04-09-2006, 03:42 PM
use jb weld
"When I was doing marine work, a Jasper rep told me that 3.0L cores were $1500 because so many of them cracked and they weren't making them anymore, so they could only reman what was out there. Jasper probably still has some, but another route would be through a marine liquidator or salvage dealer. Hard to say if theirs will be sound, but it might not be as bad as yours. I would also avoid using RV antifreeze for winterization unless you have a way to drain the water and then just run it on antifreeze so it gets into all of the nooks and crannies. I had a 50 gallon Rubbermaid tub and we bought -100 degree juice in barrels. On an i/o, I would have a bilge pump with a hose and muff to run the motor with, and when I would see that the temperature was stable, I could shut it off. Then it was checked with a refractometer for burst temperature.
All of that sounds expensive, but if you have a bunch of friends who own boats and would be willing to share the cost, everyone could get together on one day and winterize all of the boats in a lot less time than separately. Everyone could help each other and make a day of it. Not bad and it sure beats having a busted motor.
Re: JB weld- if it's an external crack only, maybe it would work. That or Marine-Tex. If it's internal, no. If the cracks are extensive, they'll just spread over time and will probably cause the motor to fail at the worst possible time."
04-09-2006, 06:15 PM
"Another solution for some (but certainly not all...) cracks is lock'n'stitch ("")."
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