JD 415 - Alternator issues

Discussion in 'Mechanic and Repair' started by avp27, Dec 9, 2007.

  1. avp27

    avp27 LawnSite Member
    Messages: 45

    hello again !

    following on from my fan belt replacement on a JD415 with a 3 cylinder yanmar. I inspected the alternator and I am not sure whether I have another issue. To turn it, it takes a bit of force, it doesn't spin freely...should it ? when you turn it it you can feel the magnets which creates a level of resistance. Just checking in to see if thats normal befoer I put it all back together....

    cheers, Anthony
  2. Restrorob

    Restrorob LawnSite Fanatic
    Messages: 11,029

    It depends on how much force you call a "bit", Can you give the pulley a spin and have it continue to spin a turn or so ?

    Was it making any kind of noise/do you hear any noise while turning it by hand ?

    I'm not familiar with this Yanmar alternator but when in the auto biz if a alternator didn't free spin at-least one turn I went looking for a reason why.

    It's anyones guess on this Yanmar, But here is the tear-down procedure in case you want to check it out;

  3. avp27

    avp27 LawnSite Member
    Messages: 45

    to answer your question, I can spin it and it will not continue to spin. I seems I have an issue !!!
  4. Beaterman

    Beaterman LawnSite Member
    Messages: 6

    Remember, this is not REALLY an alternator, its basically an external stator that produces AC voltage. It will not likely spin "freely" (not sure if it would spin a full turn by hand or not) and feeling each magnet (almost like clicks or detents) is a good thing. If there is nothing making contact internally, mount it up and check the voltage across the two pins in the connector. Should get a minimum of about 26-28 volts (AC) just like any other stator. These things are typically quite bulletproof.
  5. avp27

    avp27 LawnSite Member
    Messages: 45

    its like how you have suggested. You can feel each magnet. I am opening it up today to see. thanks mate
  6. avp27

    avp27 LawnSite Member
    Messages: 45

    replaced the bearing. all good now. thanks

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