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  1. #1
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    Default Crap! Cracked block 305 Mercruiser - options?

    Guys, I have had lots of help here on my engine re-power project,,,removing a 1985 200hp 305 5.0L and replacing it with a 350 5.7L Vortec that is a bit newer. So, I was also asking ideas on what to do with my 305 when it'sout of the boat - sell it? Part it out? or, what I was leaning towards, buy a cheap boat with a nlown engine, put it in there and sell the boat. I had a deal ready to go and I would have made about $1k or so after all was said and done.

    SURPRISE!!!!! I find out today that my 305 was NOT winterized properly!!! Water leaking out the block and a manifold (or both). I didn't see it, just what the guy doing the engine swap reported to me. He says the engine was running fine, idling smooth but water coming out all over! CRAP.

    Now, I guess the good news is I have a 350 sitting there for him to put in my boat, but looks like my plans for the 305 aren't so simple now! I've searched a biy on cracked blocks and see so different options. I have no intention of spending $1000s on this as I only wanted to use it in a boat I was going to sell to cover the cost of repowering my boat. I just read about JB Weld as a possible fix for a cracked block - could this apply here?

    Can a welder fix a cracked block for a reasonable cost? Any other ideas? If I have to I'll just part out what's usable and be done with it.

  2. #2
    Chief Petty Officer Mkos1980's Avatar
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    Default Re: Crap! Cracked block 305 Mercruiser - options?

    Part it out or scrap it.
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  3. #3
    Honorary Moderator Emeritus Don S's Avatar
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    Default Re: Crap! Cracked block 305 Mercruiser - options?

    have no intention of spending $1000s on this as I only wanted to use it in a boat I was going to sell to cover the cost of repowering my boat. I just read about JB Weld as a possible fix for a cracked block - could this apply here?
    IS this another "How to screw the prospective buyer" thread?
    If you plan on keeping the boat and using it, JB weld MAY work for a while, while you look for an engine. But to patch it like that so you can sell it is nothing more than a ripoff.
    Don S.


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  4. #4
    Fleet Admiral HT32BSX115's Avatar
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    Default Re: Crap! Cracked block 305 Mercruiser - options?

    If you want to repower that other boat why not pick up a used truck 350 on craigs list and put it in the boat?

    At least you'll be selling the boat with a known "good" engine.

    Please don't foist a cracked block off on someone else!
    73 de Rick
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  5. #5
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    Default Re: Crap! Cracked block 305 Mercruiser - options?

    Please don't try to sell that block.
    It might come around and bite more than you.

  6. #6
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    Default Re: Crap! Cracked block 305 Mercruiser - options?

    Guys, I don' need an ethics lecture here......I would certainly NOT sell it IF whatever fix I did wasn't a good, long-term solution! IF JB weld only hides a problem that will soon return, then no, it's no a fix I want to do.

    So, so far JB Weld isn't looking like the solution. If I have the engine off the boat (no gas tank!) can it be welded to permanently fix the crack? Again, if it doesn't really do the job then I won't have it dine.

    So far. parting it out may be the best way to go.......NOT what I wanted to do!

  7. #7
    Honorary Moderator Emeritus Don S's Avatar
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    Default Re: Crap! Cracked block 305 Mercruiser - options?

    At a minimum, you need a new block to fix the problem properly. Even if you did patch with JB weld, it would only be long enough to find if you had internal/invisiable damage to go along with the external cracks.
    Don S.


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  8. #8
    Chief Petty Officer dvan1901's Avatar
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    Default Re: Crap! Cracked block 305 Mercruiser - options?

    A cracked block can be welded, but it is probably as expensive as replacing it. From what I understand, because it is cast iron, you have to strip the whole block down (which you would have to do to replace it anyways) and heat the whole block to a uniform temp and weld a piece at a time. This is assuming you can find someone to weld cast iron. I had a cracked block last year and looked into this and it was easier, cheaper, and better to just replace it. You can get a new block from lots of places.

  9. #9
    Moderator Bondo's Avatar
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    Default Re: Crap! Cracked block 305 Mercruiser - options?

    Ayuh,.....

    Fixing a Freeze Cracked V-motor usually Isn't possible.....

    Mainly because of Where they Crack......

    If it's Cracked just Under the block's Deck, where the Head bolts on,...
    The Deck is No Longer Flat.... No amount of welding or JB weld will fix that.....
    Another common spot is in the Lifter Valley.... Also another spot that doesn't take well to Welding,+ Especially JB Weld,.... Too Oily....

    I'd say at this point,.... Your Only Option is to Junk It....
    Any Grease is Better,..... Than No Grease at All.......

  10. #10
    Petty Officer 1st Class wil7483's Avatar
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    Default Re: Crap! Cracked block 305 Mercruiser - options?

    Quote Originally Posted by tmh View Post
    Guys, I don' need an ethics lecture here......I would certainly NOT sell it IF whatever fix I did wasn't a good, long-term solution! So far. parting it out may be the best way to go.......NOT what I wanted to do!
    It appears to me that you do need an ethics lesson. By your own words If you can find a long term fix for it you would still consider selling it. Selling a cracked block whether you fix it or not is unethical. You have a piece of junk and that is all there is to it. Part it out if you wish. You will still make a few dollars that way and then take the block to the junk yard or sell it for scape. You wanted options, well then you have options. Everyone has said the exact same thing. Don't try to fix the thing to pawn it off on someone else.


    1988 Wellcraft Elite 222 XL w/ 350 5.7 SBC and Alpha One

  11. #11
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    Default Re: Crap! Cracked block 305 Mercruiser - options?

    I never said, nor even hinted, that whatever fix could be done would not be disclosed to a buyer. Of course, if it were a fix that was widely considered a permanent fix and "good as new" I WOULD have been fine with that as would an informed buyer. Lower price maybe, but on the level.

    This is exactly why I asked the original question - to educate myself on whether this type of issue could be properly fixed for a reasonable cost. Looks like the experts have weighed in and it CAN'T. I'm fine with that and now I know.

    btw, I have sold nearly 300 items on eBay over the years.....and I have a 100% PERFECT feedback rating......this isn't easy to do unless you are implicitly honest in telling the good AND bad of what you're selling - which I always do.

    Thanks to those who helped educate me on this subject. I really appreciate it.
    Last edited by Don S; May 4th, 2008 at 12:21 PM. Reason: No name calling

  12. #12
    Fleet Admiral Gary H NC's Avatar
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    Default Re: Crap! Cracked block 305 Mercruiser - options?

    OK,Play nice guys!! No one is here to bash each other...


    1981 ChrisCraft 210 Scorpion K,175 Johnson SeaHorse

  13. #13
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    Talking Re: Crap! Cracked block 305 Mercruiser - options?

    The older DC Chat is back?

  14. #14
    Honorary Moderator Emeritus Don S's Avatar
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    Default Re: Crap! Cracked block 305 Mercruiser - options?

    Quote Originally Posted by Coors View Post
    The older DC Chat is back?
    No, it's not.
    Don S.


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  15. #15
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    Talking Re: Crap! Cracked block 305 Mercruiser - options?

    lol. It started to sound like it was.

  16. #16
    Petty Officer 1st Class wil7483's Avatar
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    Default Re: Crap! Cracked block 305 Mercruiser - options?

    Edit..
    Last edited by Don S; May 4th, 2008 at 05:05 PM. Reason: That's it.


    1988 Wellcraft Elite 222 XL w/ 350 5.7 SBC and Alpha One

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