Water in this oil or not?

[Fishermark]

Mechanic at a Marine shop. He said theres not supposed to be water in there (the intake manifold under the carb)

As there water in the oil he said it must be the block

Like the others I think your mechanic is confused. My bet is that you will find the side of the block cracked under the manifold when you take it off.

 

[Grub54891]

Or the mechanic stated there should be no water in the intake side of the manifold. In a way he is right, but the exhaust cooled by water is part of the manifold. Mabey just a little confusion about the answer you got. As I said before, my intake/exhaust was only slightly cracked, but all the core plugs were blew out, and the block cracked under the manifold. Bought it that way..... Repaired the block and manifold, replaced the core plugs and hoped for the best. Never had any issues since. Sometimes ya get lucky.....

 

[lister]

How did you repair it? Weld it?

 

[Bondo]

How did you repair it? Weld it?

Naw, ya replace the cracked parts,....

Cast iron welds very poorly,.....

If any leaks were only to the outside, 'n not into the oil cavity, epoxy can be used,...

 

[Grub54891]

I dremmeld out the cracks, and jb weld. It's been holding 5 years now. I expected failure at some point but it has not happened. I honestly thought it was junk but I was lucky so far......I have another motor as a spare so I'm not to worried if this one fails.

 

[JerryIrons]

You should post a pic of what you did

 

[Rick Stephens]

I dremmeld out the cracks, and jb weld. It's been holding 5 years now. I expected failure at some point but it has not happened. I honestly thought it was junk but I was lucky so far......I have another motor as a spare so I'm not to worried if this one fails.

Believe it or not, I did that on the side of the highway on a 3406 Cat engine while hauling a excavator up a mountain. That one broke a lifter and pushed a now severely bent pushrod through the side of the block right behind the fuel pump. Was an external crack with no pressure oil cavity on the inside. Probably still running 25 years later. Not same as external on one side and water jacket on the other, but at least a fresh cooled Mercruiser has no pressure in the water jackets. Biggest risk is later on rusting around the JB Weld or it cracking further.

 

[Grub54891]

Well I could post a pic, when I get some. But after I pulled the motor and re-gasketed it later just to make sure there were no oil leaks, I cleaned the motor and painted it. You can't even tell where the cracks were, when I applied the jb I gently roughed the surface of the jb with a cotton rag to match the cast as best I could.

 

[thumpar]

Since yours is internally cracked also JB weld is not going to fix it.

 

[Fishermark]

Since yours is internally cracked also JB weld is not going to fix it.

That's the bottom line.

 

[lister]

No Title

SO I have the chance to get a replacement motor for $400.
Picture below. (picture 1)
It LOOKS the same as mine although the valve cover is slightly different, the tube from the carb goes into it in a different place and i dont see the filler cap.
Could just be a crap picture but everything looks similar.
Would it have to be EXACTLY the same or are these fairly similar bellhousing/fitment to the outdrive?

Im hoping its the same and I wouldnt even need the starter / carb / alternator and could sell them

My existing one if is the second pic

 

[alldodge]

The block is the same but the engine is older then yours, guess late 70's to early 80"s. Before buying you want to do a compression test and hear it run long enough to get it warm. Rust on the exhaust surface can give me concern. Get the serial number

 

[lister]

yeah im probably not going to be able to test it, its already out of the boat as you can see.
This situation really sucks, the only way to be sure im not going to waste alot of money is to spend $3000 on a new one. And that aint gonna happen

and please dont say "hey you know what BOAT stands for dontcha? eh?"
YES I DO ! Heard that so many times since this issue

 

[alldodge]

It does suck, but I'm finding reman 3.0 for 2K

Other options is look for a junk boat with motor, or just a short block rebuild if you head is good

 

[lister]

This is supposed to be a junk boat with a motor but im not sure im going to be able to see it running.
He's sending more pics tonight. I'm also going to take the intake manifold off mine tonight, see if I can see any crack on the engine

 

[alldodge]

You know most everyone here is talking a cracked block, including my self. Before you go all the way and buy another motor, like you said, remove manifold, then the head and oil pan. Look the motor over real good to verify the block is cracked

 

[Rick Stephens]

I'd be nervous about an engine with that much rust on it. But what are the alternatives? I just sold a 26 year old 3.0 for $1250 as a complete bobtail unit. With a battery, water and fuel line in a gan can it fired right up and ran nice sitting on a trailer. As I told the buyer of my motor, it is actually cheaper to buy a motor still in a junk boat than a pulled motor that is provable run condition.

Rick

 

[Fishermark]

You know most everyone here is talking a cracked block, including my self. Before you go all the way and buy another motor, like you
said, remove manifold, then the head and oil pan. Look the motor over real good to verify the block is cracked

Exactly.

And before that, do what Bond-o suggested in post #5 and block the water passages off and pressurize the block and see where (or even if) it is leaking / cracked.

 

[lister]

yeah im planning to remove the intake today and have a look. I've never removed a head and I cant pull the engine myself but I'll see what i can see.


Could you explains Bond-O's idea in lamens terms?

 

[lister]

No Title

Block this hose obviously. What else? The manifold needs to stay on id guess............