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12v71 Detroit electrics

Discussion in 'Engines' started by Nails, Jul 10, 2015.

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  1. Nails

    Nails New Member

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    Hi I am looking at a Halmatic 70 odd ft with 12v71 s in her. the electric are 32 volt ! And I think the starter also 32volt could you change to 24 volt or 12volt without much expense Also the engines haven't been run for two years what precautions should be taken on start up . So many more ??? But this will do for a start .I am in Australia thanks in advance .
  2. Capt J

    Capt J Senior Member

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    Yes, you could change the starters and alternators to 24 volts fairly easily and cheaply. The next question is the biggie.... I would take the airbox inspection ports off and shoot light oil in there and turn them over by hand to circulate it and lubricate it. You can only rotate the engine the same way it turns normally or you'll snap the water pump shaft off.
  3. Bill106

    Bill106 Senior Member

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    To Capt J's advice I'll add a BIG warning when you bar them over to make sure the stop solenoid (which also needs changing to 24V) is engaged! If they have good compression there's a possibility they will start, with a big breaker bar on the crankshaft nut that can get ugly in a hurry!
  4. dennismc

    dennismc Senior Member

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    You would also have to change battery chargers and other 32v motors, lighting, etc to match, check wiring sizes also. major expense to say the least.
  5. Capt J

    Capt J Senior Member

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    You could also yank the emergency shutdown flaps on the air intake and don't need electric for that.
  6. dennismc

    dennismc Senior Member

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    Why would you disconnect the safety flaps for runawayt protection, a stop solenoid does not prevent a run away, may overspeed.
  7. Capt Ralph

    Capt Ralph Senior Member

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    OR, Leave all 32Vdc. There are some 32Vdc fans in your area I hope will respond to your post. Please search past threads on YF for more good reading. Nothing to be scared of at all.
    We still have our 32Vdc Bertram. Lots of ole 32Vdc Hat's still around.
    It's not your usual setup but works well.
    I'm also a 71 fan.
    Pull the impellers, bar them over a few turns by hand with the valve covers off.
    Have a quiet party with a quiet person or two leaning over each head watching the rockers. Watch the valves and injectors work and return up correctly.
    Other than the injectors trying to squirt fuel, no ting sounds should be heard.
    Pour a pint of mystery oil in a filter, fresh impeller back in and crank them up.

    If your new to ole Detroit's and nervous, find a good local tech.

    71s rule,

    rc
  8. Capt J

    Capt J Senior Member

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    Not remove them. When you pull the release on them, it closes off the air intakes on the motor and the motors will not allow enough air into the motor to run.
  9. rgsuspsa

    rgsuspsa Member

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    Neither the raw water pump, nor the fresh water pump, not their respective shaft and internal components will be harmed in the least by rotating the engine in either direction.

    If barring the engine over via the bolt which secures the torsional damper to the nose of the crankshaft, an engine the size of a 12V-71 has sufficient internal friction that the bolt can potentially be loosened by attempting to rotate the engine in a counterclockwise direction, as viewed by a person standing in front of the engine and facing aft. This can be catastrophic later when the engine is running, potentially allowing for detachment of the torsional damper and consequential damage to engine and boat, as well as to any person(s) in the vicinity.

    Thoroughly understand what you are doing before you do it, or have a competent professional involved.

    Ron Sparks
  10. Capt Ralph

    Capt Ralph Senior Member

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    Ron
    I mostly agree. My offer of removing the impeller was to ensure that any dried, deteriorated rubber parts of a 2 year old impeller with unknown history before setting up would not fall apart and enter into the cooling system. With the impeller removed, the direction of turn does not matter. Facing the engine, turn to the right (tighten). Your just making sure it's free and the valves are not stuck down. In a revolution or two, the oil, fuel & clutch pumps would not care.
  11. rgsuspsa

    rgsuspsa Member

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    Hello Ralph: Thank you for your comments.
  12. dennismc

    dennismc Senior Member

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    Sorry Cap J I always thought if you yanked something then it was removed from its normal location and usually repaired or discarded, must be an Irish thing.
  13. Kafue

    Kafue Senior Member

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    Why are you changing from 32 volt?
    I have 32 volt, 24v, and 12 volts on my boat and see absolutely no reason to change the alternators or other 32 v items.
    Most bilge pumps handle all the above. Get a spare 32 v Alternator if you are heading on a long journey, other than that, why go to the cost and effort to change?
  14. g collis

    g collis Member

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    I'm sure you have had all your questions answered by now. But I'll throw in a couple of penny's here. The 71's are simply one of the best engines DD ever built. I swear they will run on sea water. Just kidding! I have 12v71's and they have never let me down. As for your 32V change over. Yes the starters and alternators are simple enough to convert and as mentioned you'll also have to change the battery chargers. But the real rub is that the entire vessel is on a 32v system. IE battery powered lights, pumps and so on. A change over can get involved and expensive. Just food for thought.
  15. Capt Ralph

    Capt Ralph Senior Member

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    71s rule.
  16. g collis

    g collis Member

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    Yes they do. No computers, fuel injection pumps or complex tuning set up. And contrary to popular belief they are economic and when well maintained they don't smoke.
  17. Capt Ralph

    Capt Ralph Senior Member

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    I'm glad Kafue did come in. I believe were on the same page when it comes to the 32Vdc issues. Why mess with something that is working well.
    G Collis came in reminding us that the 71s are a good breed of ole 2 strokes.

    I was looking at a Halmatic years ago in Palm Beach with the original RR mains. I am so sorry I did not jump on that ship and regretted it since.

    So, What ya gonna do?