4.3 with a cracked block

[mixd]

I bought a fixer upper boat for a for very little money.I was told it had cracked heads from bad winterizing.As it turned out,it has a cracked block.It is a 4.3 omc with a cobra outdrive.What are my options?A mechanic told me i could just get a 4.3 from a car and install it.Is this true?If not,what are the required alterations to do so?I have been an outboard person only until this point so i dont know a thing about this.

 

[dingdongs]

Re: 4.3 with a cracked block

not a good start and if it doesn,t owe you much may be time to break it for its sum of parts and get yourself a runner as omc hardwear is getting rarer by the day.

 

[mixd]

Re: 4.3 with a cracked block

Can i get away with using a regular4.3 block?

 

[searay3]

Re: 4.3 with a cracked block

Cracked heads are never the only issue with poor winterizing. Look closely at the exhaust manifolds. My bet they are cracked as well. A truck block of that vintage should work, will need brass core plugs (freeze plugs) and all the marine life support: starter, alternator, carb, ign, fuel pump. Those would not be affected by the winteriztion, or lack there of. This will probably cost a few thousand to put back together. Unless you are doing the work yourself and have access to a salvage boat for good parts, you may be better off parting it out and getting something that runs with more available parts. Not bashing it, but cheap boats rarely stay that way. Some have had good luck finding OMC parts, but the cost factor may get in your way.

 

[mixd]

Re: 4.3 with a cracked block

I have a friend that is good at rebuilding car engines,but has no experience with marine applications.So far the manifolds and heads seem alright,but we will get them checked out.We dug into it today and found the motor even still turns.There is no sign of water in the oil,but a visual inspection showed a crack.If i were to get a truck 4.3 do you think i could use the heads off of this one?

 

[searay3]

Re: 4.3 with a cracked block

You could. That brings to mind maybe a short or long block from a rebuilder. Check the intake manifold closely and the exhaust manifolds. It would be a stretch, but maybe the po drained the manifolds and not the block?

 

[Bondo]

Re: 4.3 with a cracked block

If i were to get a truck 4.3 do you think i could use the heads off of this one?

Ayuh,... Use the truck Long Block,... That's block, And heads...
Then bolt all the other Stuff off the old motor onto it....

 

[mixd]

Re: 4.3 with a cracked block

Thanks guys.I guess the next step is to remove the motor.Do i need to remove the outdrive to remove the motor?

 

[Bondo]

Re: 4.3 with a cracked block

Do i need to remove the outdrive to remove the motor?

Yes...

 

[mixd]

Re: 4.3 with a cracked block

I guess there's nothing to lose at this point.Only some knowlage to gain.

 

[Bluestream]

Re: 4.3 with a cracked block

Thanks guys.I guess the next step is to remove the motor.Do i need to remove the outdrive to remove the motor?

If you have room you can slide the motor forward and then raise it up and out with the outdrive on, but it should come off anyway for inspection and maintenance

I would look for a used 4.3 marine engine before going with the auto block. Should cost $1000- $1500 for a good complete engine.

What budget do you have for this engine replacement?

 

[Dakota47]

Re: 4.3 with a cracked block

i would go to the junk yard and find a good 4.3 out of a S-10 pick-up or blazer and slap that puppy in there..

 

[Joshua Nichols]

Re: 4.3 with a cracked block

If you have room you can slide the motor forward and then raise it up and out with the outdrive on, but it should come off anyway for inspection and maintenance

I would look for a used 4.3 marine engine before going with the auto block. Should cost $1000- $1500 for a good complete engine.

What budget do you have for this engine replacement?

I bet I can yank off my outdrive in maybe twenty minutes?. Might as well pull it.. Makes stuff easier. Work smarter not harder

 

[Gary H NC]

Re: 4.3 with a cracked block

Figure on buying new exhaust manifolds. That is about 950 bucks right there.
I would NOT use the old manifolds after all that work.

 

[Bluestream]

Re: 4.3 with a cracked block

I bet I can yank off my outdrive in maybe twenty minutes?. Might as well pull it.. Makes stuff easier. Work smarter not harder

I'm sure you can; I can get mine off in 5 mins. OP asked if he could remove the engine without the drive, and I answered his inquiry.

AS for pulling it, I advised him to do so...

 

[bruceb58]

Re: 4.3 with a cracked block

I'm sure you can; I can get mine off in 5 mins. OP asked if he could remove the engine without the drive, and I answered his inquiry.

He's just not going to be able to put it back on without removing the drive.

Not going to even talk about all the other reasons he should be pulling the drive.

 

[Danny Mc]

Re: 4.3 with a cracked block

Where is the block cracked, if you can run it and don't see water in the oil, and the crack is on the out side of the block. I use Marine-Tex or JB Weld to fix, heck it's worth a try, if you still got a prob then pull eng.

 

[mixd]

Re: 4.3 with a cracked block

I have spent some time looking for a donor boat.I found one with a 4.3l mercruiser set-up with an alpha 1 outdrive.If i go ahead with the swap do you think i will be able to sell the omc components?What should i be asking for it?

 

[Bluestream]

Re: 4.3 with a cracked block

with the outdrive on, but it should come off anyway for inspection and maintenance

As I said^^^^^^^^^^^^^^^^^^^^^

The price of the OMC parts will depend on the condition of them, the time of year you sell them, and where you advertise them for sale. I live in the same town as you, and in this area Kijiji is the only way to go and it's free.

What do you have for sale?

 

[mixd]

Re: 4.3 with a cracked block

Where is the block cracked, if you can run it and don't see water in the oil, and the crack is on the out side of the block. I use Marine-Tex or JB Weld to fix, heck it's worth a try, if you still got a prob then pull eng.

The crack is on the inside,but,there was no sign that water got to the internal components.I found no rust stains and was able to rotate the motor without much trouble.The previous owner said that he ran it this way for the last run on the lake.He claims that a marine mechanic told him the heads are cracked.Could the crack i saw be just a lamination spot peeling off?