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Kaw FD750D Overcharging??

Discussion in 'Mechanic and Repair' started by jwscarab, Oct 8, 2009.

  1. jwscarab

    jwscarab LawnSite Member
    Messages: 53

    Hello! I bought a used 2005 Scag TT this spring. The old owner just replaced the battery. I ran most of summer, then it wouldnt start. Battery was DRY - needed tons of water. I replaced battery with another new one and it started right up!

    BUT, I then checked the voltage across the battery - its 17.5V

    Is my voltage regulator definitly the problem here?? I hate to spend $200 and find out I missed the problem!

    Thanks so much!!
  2. Restrorob

    Restrorob LawnSite Fanatic
    Messages: 11,029

  3. jwscarab

    jwscarab LawnSite Member
    Messages: 53

    Thats the price I have found online at 2 different places. I have not called dealer yet.

    Its a FD750D
  4. jwscarab

    jwscarab LawnSite Member
    Messages: 53

    OK, dealer wants $133 - thats a lot better!!

    But he mentioned checking stator first - at 28V

    I am not electrical genius, but not toooo stupid either.....lol. Could somebody help me with how to check stator voltage?? then reg voltage??

    Thanks VERY much.

    p.s. - I DO plan on buying the Kaw service manual, but I dont have one as of now.
  5. Ruben Rocha

    Ruben Rocha LawnSite Senior Member
    Messages: 577

    I believe if you search for stator here you will find some posts by restorob.
    But it should be like 28volts ac usually I think before the regulator.
    to test remove the connector from the regulator and measure the voltage from the stator.
    Of course the engine running full rpm
    The regulator changes the voltage from ac to dc.
  6. Restrorob

    Restrorob LawnSite Fanatic
    Messages: 11,029

    As Ruben mentioned the stator puts out AC voltage so make sure your meter is set on AC when performing the unregulated test, You will most likely find the stator good since it is over-charging.

    Did you click on the link I posted in my first reply ??? Regulator 68 bux......

    Test as below;


    Regulator out-put voltage is checked at the battery like you have already done.
  7. jwscarab

    jwscarab LawnSite Member
    Messages: 53

    Great info - and I do apprectaite it! I will test it tomorrow and let you guys know what I found out (for others reference too). And I did miss the link you added resto... Thanks!! Awesome price!
  8. jwscarab

    jwscarab LawnSite Member
    Messages: 53

    Hi all. I checked as shown. I think all is ok, but let me ask this. When I run the mower at 1/2 throttle, I get 28.6V ac, but when I run it at full throttle I get 36ishV ac. I dont have a way to see when I am running at 3000rpm.

    Is the 36V at full throttle too high and burning up the regulator? Or are these the numbers I should expect??

    Then, jumping across the battery it read 15.5v dc half throttle and 17.5v dc full throttle.

    If sounds ok, I will order the voltage regulator!!

    Thanks so much!
  9. East Coast Lawn Choppers

    East Coast Lawn Choppers LawnSite Member
    Messages: 134

    I've had most around 33VAC at full throttle, seen some up around 35 or so, the regulator is just what it says a regulator. The 26VAC is a minimum. I never seen a max posted anywhere. I know on the kohlers the test is any thing over 28VAC the stator is good. The regulator does two thing mainly... it has a bridge in it to convert ac to dc, then it has a regulator in it that should regulate the voltage to approx. 13.8-14.7 depending on the regulator.
  10. Restrorob

    Restrorob LawnSite Fanatic
    Messages: 11,029


    It's the minimum voltage that denotes if you have a faulty stator.

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