Novice electrical questions

Discussion in 'Boats, Blinds, & Gadgets Forum' started by Montauker, Feb 18, 2018.

  1. Montauker

    Montauker Elite Refuge Member

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    Yesterday my cranking battery was dead so I tried to use jumper cables to jump the motor from the trolling battery (located in the bow). Engine would crank but not start. 60HP 4 stroke, cables are 16 foot heavy gauge automotive. Is that an amp problem caused by the length/size of the jumpers?

    So I moved the trolling battery to back of the boat and direct to motor connection, no problems, started immediately.

    Next question- once the motor started I could not disconnect the battery without the motor shutting down. Is this a 4 stroke thing. I don't recall this being an issue from my old two stroke days.
     
  2. perfmarine

    perfmarine Elite Refuge Member

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    Maybe a bad jumper connection or a dead shorted battery. You should never unhook a battery when a motor is running, you could damage the charging system. This is why I told Interstate batteries to go away from wing nuts on cranking batteries, too many people just tighten them with there fingers and they vibrate loose.

    Motors with a computer need 12.5 volts to trigger the computer and spin fast enough to trigger the CDI ignition system.
     
  3. Montauker

    Montauker Elite Refuge Member

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  4. Rubberhead

    Rubberhead Elite Refuge Member

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    Yes kind'a but it's really a voltage drop problem, but "yes". Shorter and/or thicker jumper cables would help.
     
  5. BAYDOG

    BAYDOG Moderator- Diver, NY Forum, Refuge Classifieds Sponsor Moderator Flyway Manager

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    Also, alternator is bad on the motor if you can't run with out a battery. And eventually you'll drain the battery to a point it won't run, and thus won't start either, any luck 3 miles from a ramp and trailer. LOL At least that's my luck.
     
  6. Montauker

    Montauker Elite Refuge Member

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    As a novice I'm not challenging you on that, but the motor is only three years old, I'd be surprised if the alternator is shot.

    I charge my battery at the house rather than rely on the motor as I typically do not run for long (typically less than 2 miles one way).
     
  7. Tailfeathers

    Tailfeathers Elite Refuge Member

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    When the engine is running, and after you revved it up to get the alternator charging, check the voltage on the posts, they should be over 12 volts. If over, like 12.5. or 13, the alternator is charging.
     
  8. Montauker

    Montauker Elite Refuge Member

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    I think I was pulling the cables too quickly, motor was at low idle for less then 45 seconds each time (only did it twice before I realized I need to stay connected).
     
  9. feetdownshooter

    feetdownshooter Senior Refuge Member

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    Look if you have a fuel injected motor (new model like you have) the first thing you need to know is you cannot disconnect the battery or it will shut it down. This is not always the case but it's very most of the time true. Secondly your cables could use a little bit of beefing but it's more likely a battery problem than anyting battery sometimes lasts forever and other times don't last very long just the way it is hope this helps
     
  10. dukhnter8

    dukhnter8 Senior Refuge Member

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    Also might not be the case on your motor but like feetdown said most efi need a battery connected to be running and need a certain cca to even think about starting so probably with loss of cca through the cables was enough not to start the motor.

    Another thing I do not know if this motor has a stator for charging but on older motors if you ever hooked up the battery backwards by mistake then it fries the stator, cheaper part at least. I did that on an older motor I had. Check to make sure its charging and if not it may be something easy, hopefully. And I would get the battery tested.
     

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