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  1. #1

    Question Opinion on buying a non running 5.7

    I'm considering buying a non running boat with a 5.7L motor, it's an early 90s.

    Current owner says it ran fine but one day on the water, after stopping for a while, it would not turn over. Apparently a mechanic had a quick look and found, fresh, water in the engine but said the engine will turn over. I'm guessing it was hydrolocked but once sparks were removed it would turn over.

    I don't think it was a winterising issue since it happened in late summer.

    What kind of a mess would I get myself into if the price is right (cheap)?

    I have experience in rebuilding high revving 4-stroke marine motor but zero experience with these big inboards.

  2. #2
    Join Date
    Sep 2008
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    Maryland - USA
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    Default Re: Opinion on buying a non running 5.7

    if you don't know that it was stored properly, best to treat the engine as a core and nothing more.....if it is in a region subject to freezing, I'd avoid it unless the hull is immaculate and you wanna spend time working on it....and then treat the engine as ballast....

  3. #3
    Join Date
    Jun 2006
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    Spotswood, NJ, USA
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    Default Re: Opinion on buying a non running 5.7

    If it was a lake boat then you MIGHT be lucky. if a salt water boat, anything over 48 hours is trashed

  4. #4
    Join Date
    Jun 2006
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    Spotswood, NJ, USA
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    Default Re: Opinion on buying a non running 5.7

    Basic 5.7 long block W/ electric fuel pump setup , 12 bolt intake $2900 delivered

  5. #5

    Default Re: Opinion on buying a non running 5.7

    It's fresh water but the failure occurred several weeks ago. I'm just exploring the possibility with this, it may not be a good idea.

    If we were to assume the mechanic that had a quick look at it got water out of the cylinders and/or fogged them somehow what scenarios could have occurred to cause the failure of water getting into the motor.

  6. #6
    Join Date
    Jun 2006
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    Spotswood, NJ, USA
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    Default Re: Opinion on buying a non running 5.7

    cracked manifold or riser, leaking gasket joint, shutting the key off with forward boat motion to get water shot up the exaust pipe, excessive people sitting on the swimplatform, to name a few

  7. #7
    Join Date
    Jun 2008
    Location
    Island Heights, NJ,
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    2,605

    Default Re: Opinion on buying a non running 5.7

    Some non oem exhaust elbows prone to water reversion...as well as some vintage OEMs.
    Capt Bob
    1969 23ft ChrisCraft Lancer
    Merc 5.7L 260HP/ Volvo 280
    1972 22ft Bristol
    Honda 7.5HP 4 stroke Long shaft

  8. #8
    Join Date
    Sep 2003
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    New Tripoli, PA, USA!
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    15,271

    Default Re: Opinion on buying a non running 5.7

    I wouldn't touch it unless the heads were first pulled to inspect the bores and see if there's a cracked block. The block cracks just bellow the heads when there's freeze damage so you can check it at the same time..

    Jeff

  9. #9
    Join Date
    May 2010
    Location
    DC Burbs/Maryland Eastern Shore
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    Default Re: Opinion on buying a non running 5.7

    If it had water in the bores, any mechanic would immediately pull the spark plugs and relieve the pressure. Then they would run the engine and go thru several oil changes. Once that was completed there would be a compression and leak-down test performed. If none of this engine-saving procedure was undertaken then you are looking at replacing the engine just because it is so suspicious. I personally wouldn't leave the dock with such a sketchy motor determining my fate.
    A replacement block is about $2500. I have doubts that this boat you are considering would be worth that kind of coin right off the bat. I suggest that you find a more reliable boat. Don't be taken in by cheap. Cheap boats are never cheap. One way or another they cost you.
    If the seller takes such awful care of the engine after a severe event like water ingress (which I don't believe...I think it has a cracked block) then you have to wonder about all the other systems.
    Practicing the ancient art of ren-ching

  10. #10
    Join Date
    Jun 2006
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    Spotswood, NJ, USA
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    Default Re: Opinion on buying a non running 5.7

    The first critical thing is draining the water as fast as possible and getting the motor running to dry it out.
    The longer it sits the more damage is done. Once thats done change the oil and filter and run the motor under load for around 2-3 hours baking all the moisture out of the motor. What is most vulnerable are the valves sticking in the guides but if you run it for a few hours it should be ok.
    fog the engine very heavily at end of season.

    if you interested in a good boat and close enough v6 SR 220 CC pm me for info
    Last edited by Bt Doctur; 10-03-2017 at 11:02 AM.

  11. #11
    Join Date
    Sep 2010
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    Jersey Shore
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    4,635

    Default Re: Opinion on buying a non running 5.7

    Quote Originally Posted by ptscon View Post
    I'm considering buying a non running boat with a 5.7L motor, it's an early 90s.

    Current owner says it ran fine but one day on the water, after stopping for a while, it would not turn over. Apparently a mechanic had a quick look and found, fresh, water in the engine but said the engine will turn over. I'm guessing it was hydrolocked but once sparks were removed it would turn over.

    I don't think it was a winterising issue since it happened in late summer.

    What kind of a mess would I get myself into if the price is right (cheap)?

    I have experience in rebuilding high revving 4-stroke marine motor but zero experience with these big inboards.

    Save your money. Don't buy anyone's junk. And it is junk.
    Chris
    Dockside Marine Services
    Jersey Shore.
    Mercruiser/Mercury Certified
    Let the insanity begin.

  12. #12

    Default Re: Opinion on buying a non running 5.7

    I did a similar project two years ago on a 2004 Sea Ray 200 that previous owner cracked block. Where it made sense to me was boat was in really great shape and only had 38 hrs on it, most importantly by the time I bought the boat and the new engine I was in it for half of book value.

    I would think you need to approach as thought the engine is shot from a purchase price standpoint. By the time you fix it to O2s point the boat probably isn't worth it. You can probably find a similar vintage running boat for similar money to the cost of repair...

  13. #13
    Join Date
    Jun 2008
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    Island Heights, NJ,
    Posts
    2,605

    Default Re: Opinion on buying a non running 5.7

    I always assume when buying a used boat that it needs a new (crate) engine and pay accordingly.
    Capt Bob
    1969 23ft ChrisCraft Lancer
    Merc 5.7L 260HP/ Volvo 280
    1972 22ft Bristol
    Honda 7.5HP 4 stroke Long shaft

  14. #14
    Join Date
    Sep 2003
    Location
    New Tripoli, PA, USA!
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    Default Re: Opinion on buying a non running 5.7

    That at least!

    We absolutely lucked out buying a 30 year old bowrider with a Mercruiser and it works super. Had to replace a few things, but the motor, trim system, OD, etc. runs like new.

    Jeff

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