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Kohler 23hp Stator question...

Discussion in 'Mechanic and Repair' started by barncat, Sep 12, 2010.

  1. barncat

    barncat LawnSite Member
    Posts: 13

    Hey guys, first post, long time lurker.
    Here's my deal. I have an Exmark Lazer Z 60"(awesome machine). It's 7 years old, w/287 hours on it. I just bought it, and noticed I was having charging issues. At first I thought it was a bad battery, as it was old.
    I replaced it, and still not charging.

    I have checked the stator, and am only getting 11-18volts. I ohmd it out, and the windings show .2ohms It's not shorted to ground.

    My question is, should I still go with a new stator, or is there a different problem I may be overlooking?

    I hate shot-gunning parts at stuff, so I'm just trying to rule out anything else.
     
  2. dutch1

    dutch1 LawnSite Silver Member
    from Jayhawk
    Posts: 2,231

    I'm not familiar with the newer stators but I would think you ought to have at least 30 VAC across the stator leads with the stator lead disconnected from the regulator/rectifier.. Your resistance across the stator lead at .2 ohms is acceptable. You should also check resistance from each stator lead to engine ground. If you have any resistance or continuity, the stator leads are shorting to ground.

    You can normally check to see if you have DC output by checking voltage across battery terminals with engine not running then with engine running. If the reading is higher with engine running you have at least some output. In addition, remove the wire that goes from the B+ terminal to the switch at the switch. You should have 13.5-14.5 from that lead to the negative battery terminal with the engine running.

    You could go to Kohler's website to download the manual for your engine and check their trouble shooting guide for the stator.
     
  3. barncat

    barncat LawnSite Member
    Posts: 13

    I have the manual(thanks tho)My DC output is right around 12.9 at full rpm.

    My no load AC(stator) output is less than 20vac. I am not sorting to ground. I'm an HVAC tech, and with Fan motor windings, they can show good windings, but when load is applied they heat up, and open up. I'm wondering if this is my problem.

    I have also read somewhere that the magnets come off the flywheel. I don't or haven't heard any noises that would indicate such.
     
  4. Restrorob

    Restrorob LawnSite Fanatic
    Posts: 11,024

    Dutch is right with 30 + AC volts, Pull the flywheel before chasing down a stator and use a puller for removal. If the magnets aren't broke loose they could be using the old pry-bar and hammer method.
     
  5. barncat

    barncat LawnSite Member
    Posts: 13

    I'm leaning towards flywheel. I ohmd the stator and regulator, both seem good to go.
    Stator was showing .2-.3 ohms. Output voltage is consistently less than 24v.a.c.

    I'll pull the flywheel later this week.
     
  6. dutch1

    dutch1 LawnSite Silver Member
    from Jayhawk
    Posts: 2,231

    It's pretty rare, in my experience at least, that when a flywheel magnet has been lost it's pretty rare when damage has not occurred to the stator. Good luck.

    Rob, you are correct on the prybar and hammer, especially for someone who does not do the job regularly. When I use this method, I am careful to use the extreme end of the prybar against the block and a closer part of the bar on the very edge of the flywheel--in other words lifting on the prybar rather than pushing down.
     
  7. barncat

    barncat LawnSite Member
    Posts: 13

    Thanks for the advice guys. I'm hoping the stator isn't damaged, but with my luck, I'm sure it is.
     
  8. Restrorob

    Restrorob LawnSite Fanatic
    Posts: 11,024

    Dutch,

    On these Kohlers it's not the prybar that pops the magnets loose, It's the sudden shock from the hammer hitting the crankshaft/bolt.

    Believe it or not rust forms under the magnets through the epoxy they use to bond them in, The least amount of shock once rusted pops them loose.
     
  9. dutch1

    dutch1 LawnSite Silver Member
    from Jayhawk
    Posts: 2,231

    I don't doubt that it can happen in that manner, Rob. I'm sure you have seen a lot more of the Kohler magnet problem than I have but I was in a shop envoirnment for 5 or 6 years and don't recall it ever occuring. On the magnet failures I observed the magnet(s) had come loose while running and the conclusion was that it was an adhesive/rust problem that caused the problem.

    I'll put that in my memory bank for future consideration.
     
  10. Restrorob

    Restrorob LawnSite Fanatic
    Posts: 11,024


    Well Dutch, I hate to admit but in my younger days replacing a top crank seal I used the prybar method. This was one of the first Commands I worked on, I know I popped the magnets loose because I drove the unit into my bay and there was no damage to the stator or other magnets.

    After having to buy the customer a new flywheel, My prybar and hammer stays in my toolbox......
     

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