Click for YF Listing Service Click for Burger Click for Nordhavn Click for JetForums Click for Perko

Alternator question

Discussion in 'Ocean Yacht' started by Boomer, May 20, 2018.

You need to be registered and signed in to view this content.
Page 2 of 2
  1. Boomer, May 28, 2018
    #21
    Boomer

    Boomer Senior Member

    Joined:
    Oct 14, 2017
    Messages:
    677
    Location:
    Seminole
    Ok...pulled all the wires on the motor from the alt..all ok...went to the bridge thinking maybe key switch was the issue...nope...all numbers and wire connections Match the other motor...ideas anyone?
  2. Capt Fred, May 28, 2018
    #22
    Capt Fred

    Capt Fred Senior Member

    Joined:
    Jun 22, 2009
    Messages:
    319
    Location:
    Long Beach CA
    I had the same issue. I replaced both of my alternators and one stayed at a cool temperature and the other would warm up and kill the battery. For the one that got warm I had to supply it with switched power on one of the spade terminals. mine would actually spark a little when connected. Problem solved after I switched off the power.
  3. Capt Ralph, May 28, 2018
    #23
    Capt Ralph

    Capt Ralph Senior Member

    Joined:
    Sep 8, 2004
    Messages:
    12,727
    Location:
    Satsuma, FL
    Need to make sure I'm reading this correctly; spade wires disconnected and alternator now cold.
    Sorry I'm late, fighting kidney stones and can't get to my archives yet.
  4. Boomer, May 29, 2018
    #24
    Boomer

    Boomer Senior Member

    Joined:
    Oct 14, 2017
    Messages:
    677
    Location:
    Seminole
    Yes, if spade wires are disconnected, the alt cooled down...get well soon!
  5. Boomer, May 29, 2018
    #25
    Boomer

    Boomer Senior Member

    Joined:
    Oct 14, 2017
    Messages:
    677
    Location:
    Seminole
    Might be my last resort...thanks for the idea
  6. Capt Ralph, May 29, 2018
    #26
    Capt Ralph

    Capt Ralph Senior Member

    Joined:
    Sep 8, 2004
    Messages:
    12,727
    Location:
    Satsuma, FL
    Make sure that purple wire is dead with key switch off, Hot with keys witch on.
    This wire is your exciter wire. It helps enable the alternator at low speed.

    The red harness wire usually would go to the + post on your starter. This is the + charge wire to the battery.

    The orange wire may be the fused B+ lead to your dash/helm for gauges and key switch. For simplicity and a better connect, it should be tied to the same point the red wire is secured to. Two high current wires crimped like that is not reliable or efficient.

    That short strap from B+ out, to the spade (tied to the orange wire) annoys the heck out of me. That is a poor rig from a previous wanna be tech.
    Last edited: May 29, 2018
  7. Capt Ralph, May 29, 2018
    #27
    Capt Ralph

    Capt Ralph Senior Member

    Joined:
    Sep 8, 2004
    Messages:
    12,727
    Location:
    Satsuma, FL
    Your warm alternator is from getting excited and doing nothing. Even draining your battery.
    My first guesses are the purple wire is hot when key is off or the leads between the spade post are backwards.

    How comfortable are you with a DVM?
    Please confirm where the orange and red wires go.
  8. Boomer, May 29, 2018
    #28
    Boomer

    Boomer Senior Member

    Joined:
    Oct 14, 2017
    Messages:
    677
    Location:
    Seminole
    purple showed a negative .08 reading with key off..other red showed 13volts....didnt check purple with key on...it is wired the same as the other motor...will it damage the electrical if I swap the spade wires?
  9. Boomer, May 29, 2018
    #29
    Boomer

    Boomer Senior Member

    Joined:
    Oct 14, 2017
    Messages:
    677
    Location:
    Seminole
    Orange wire goes nowhere...dead at the end....one small red from the alt lug to a spade and the big red from alt to the starter lug that the battery is connected to...purple goes to a bus bar that attaches to 2 reds and disappears behind the fuel tank
  10. Capt Ralph, May 29, 2018
    #30
    Capt Ralph

    Capt Ralph Senior Member

    Joined:
    Sep 8, 2004
    Messages:
    12,727
    Location:
    Satsuma, FL
    Dead at the end; Not connected to anything?
    This may be a external feedback strap. Usually not used on Delco's.
    Perfect.
    Strange. Lets still find if this purple wire goes + hot with either key switch on.

    NO. Still need to know if the purple is keyed hot for this try to be preformed smartly.
    The third male spade forward of the side by side spades may go to a indicator light. Lets try not to touch this lead with any hot leads.

    Do you have Battery parallel relays?
    Do you have combiner relays?
    Do you have Battery Diode Isolaters?
    How many battery banks do you have?
    How do we know the other alternator is charging or wired correctly?
  11. Boomer, May 29, 2018
    #31
    Boomer

    Boomer Senior Member

    Joined:
    Oct 14, 2017
    Messages:
    677
    Location:
    Seminole
    None of that fancy stuff you mentioned...each motor has its own battery..no parallels...other motor charges and alt does not get hot...i traced all the wires in the er and they are exactly the same...would a faulty key switch cause this issue? Wee reverse the red and purple spade tomorrow to see if the motor charges and it stays cool when not in use
  12. Boomer, May 30, 2018
    #32
    Boomer

    Boomer Senior Member

    Joined:
    Oct 14, 2017
    Messages:
    677
    Location:
    Seminole
    Turned key on and purple went hot..switched the purple and red on the spades...think we got it! The spades must be reversed on the newer alternators... Thanks everyone!
Page 2 of 2