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Thread: Raw Water Cooling questions??

  1. #1
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    Raw Water Cooling questions??

    Guru's,
    I am starting my 1968 18' project and have a few questions about water cooling. First question is:
    For Hp reason...should I look for a circulating pump for my 350 small block or a raw water pump? Should this be belt driven or crankshaft driven? I do have a crossover tube setup that I purchased cheap.
    Second do I even need one due to having the pump in the Alpha drive lower unit pickup? Or do I need both?

    Any guidance or convincing will be greatly appreciated!

    Mike

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    set up an Alpha like Merc does

    I would suggest running with a thermostat and circ pump with an Alpha drive just the way Merc sets them up. I would not rely on the raw water pump in the drive and a crossover to cool the engine properly.

    You could add a crank or belt drive pump if you really want to run with the crossover but those will likely cost more than a circ pump. Either way, I would still suggest running with a thermostat.
    Thank you, Patrick
    1994 18' Classic 350Mag Alpha

    Previously owned Donzis -
    1996 22' Classic, 502Mag Bravo
    1987 20' Minx, 350Mag Alpha
    1975 18' Classic, 350Chevy Volvo 280

  3. #3
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    An Alpha drive raw water pump doesn't really provide enough water to use a crossover, so a circulating pump is always recommended w/that drive.
    I suppose the alpha impeller could be removed and a crank driven raw water pump could be added.
    IMHO, the best way to make your engine happy is to add a transom pickup, and a crank driven raw water pump.
    The Alpha impeller would be removed along w/the raw water connecting hose through the transom (the hole in the transom would be blocked off.
    George Carter
    Central Florida
    gcarter763@aol.com
    http://kineticocentralfl.com/


    “If you have to argue your science by using fraud, your science is not valid"
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    I think Merc still uses that stock Alpha set up to this day. it was used in the pre Alphas also. so for at least 35 years and they haven't changed it. I think it would be a safe bet that you can say the system works. I'd wager there are more Alpha drives on earth using that setup then all other out drives combined. My answer is new Impellor and a stock belt driven circulator pump on the front of the engine. I have a Jabsco bronze raw water pump on my cruiser does the same exact thing as the raw water pump in my Alpha drive on the Minx. The difference is it cost about $700 for the Jabsco. That's a lot of beer and gas
    machinist ,bore it deeper,ream it bigger, and lap it to a fine finish



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    Need the pump in an Alpha

    I belive that the raw water pump and water flowing thru are required to keep an Alpha cool.
    I have heard of people using the Alpha raw water pump to just cool the drive and use a pickup and other raw water pump to cool the engine. Sounds like extra stuff that would only be needed for a supercharged engine.
    I know many guys that have run the standard Merc setup with 400HP+ stroker motors. Stock Alpha raw water pump and circ pump on the engine is the way I'd go.
    Thank you, Patrick
    1994 18' Classic 350Mag Alpha

    Previously owned Donzis -
    1996 22' Classic, 502Mag Bravo
    1987 20' Minx, 350Mag Alpha
    1975 18' Classic, 350Chevy Volvo 280

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    Thanks guys for the replies!! Still in the beginning stages so have some things to think about.

    Thanks again!
    Mike

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    I used a marine alloy circulating pump on my Alpha/4.3 to keep the weight down. I couldn't justify any other performance benefits from moving away from a circulating pump with the Alpha.

    My question now I'm building a SBF for the Ski Sporter would be... what about an electric circulating pump?

    4.3 V6 build 032013 003.JPG
    Sean Conroy,
    1964 Formula Jr. (hull #2) project

    1972 Greavette Sunflash III
    1981 Kavalk Mistral project

    "A man can accomplish anything... as long as he doesn't care who gets the credit."

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    water pump on sale

    I'm not sure this will fit your application, but Amazon has a lightning deal sale (good for the next 2 hours) for a Jabsco pump. Supposedly it is a $460 list price but on sale for a short time for under $100, with free shipping:
    http://www.amazon.com/dp/B000O8D1RC/...d_p=1980506282

    BTW, I have no financial interest in this. I'm just highlighting a potential good deal for someone.

    Davis

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    Quote Originally Posted by ivypandas View Post
    I'm not sure this will fit your application, but Amazon has a lightning deal sale (good for the next 2 hours) for a Jabsco pump. Supposedly it is a $460 list price but one sale for a short time for under $100, with free shipping:
    http://www.amazon.com/dp/B000O8D1RC/...d_p=1980506282

    BTW, I have no financial interest in this. I'm just highlighting a potential good deal for someone.

    Davis
    Thanks for the link! I just got one for a friend of mine whose pump was leaking (sounds like a personal problem - lol). Amazon charged sales tax, but still only $108.

    1971 Donzi 18' 2+3
    1985 Eliminator 23' Daytona Offshore - Kevlar hull
    1988 23' Donzi CC F-23 with 250HP EFI Mercury OB
    1989 28' Team Warlock Offshore - single 548CID/600HP
    1990 23' Warlock Offshore - single 525HP
    Bill from Denison, TX - Lake Texoma

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    Thanks for the link but I missed the Lightning deal! Crap I would have gone that way.

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    Another chance

    Quote Originally Posted by DonziNUTS View Post
    Thanks for the link but I missed the Lightning deal! Crap I would have gone that way.
    Here is a different, better Jabsco pump (62 GPM versus the previous 14 GPM) that went on sale today at 8pm EST for $219.99:

    http://www.amazon.com/gp/product/B00...d_p=1980506282

    Before the sale, it was priced at just over $337. The sale ends in about 3 1/2 hours so I hope you see it in time.

  12. #12
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    Here's a link to my personal favorite crank driven Johnson pump.
    They're used on both SBC and BBC engines, and the good news......they're under $200. All the time.
    I've used several from this supplier and no problems.

    http://www.marineexhaustmanifolds.co...ater-pumps.htm
    George Carter
    Central Florida
    gcarter763@aol.com
    http://kineticocentralfl.com/


    “If you have to argue your science by using fraud, your science is not valid"
    Professor Ian Plimer, Adilaide and Melbourne Universities

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