Kohler Starter Question

Discussion in 'Mechanic and Repair' started by mcambrose, Aug 8, 2006.

  1. mcambrose

    mcambrose LawnSite Senior Member
    Posts: 511

    I have three of the Nippondenso Kohler starters which had solenoids that got weak, so I ordered some off Ebay. I cleaned the starters and put the new solenoids on. The starters all work good when bench tested using a battery charger as the 12V source. When I put them onto older walkers the solenoids dont work consistently. Sometimes when you turn the key, the solenoid will just click. Does anyone have an idea of why they work on bench and not in mowers. I have tried connecting a wire directly from the battery to the 12V terminal usually connected to the ignition circuit and no change. I was thinking that maybe the grounding through the frame was not as good in the older units because of corrosion or something else over time. I have not yet tried using a grounding wire directly from the battery. Does anyone else have any ideas? Thanks for any help. I have replaced each of these three starters with new starters and they work fine, so that is something else that baffles me.
     
  2. Jim@MilkyWay

    Jim@MilkyWay LawnSite Senior Member
    Posts: 472

    Hey you
    It's late and I am off to sleep, but will post reply tomorrow if I get a break. I have not been on the forum lately, as it has been super busy at work this week.
    Check the voltage drop across four points of the starter solenoid while starter is engaged. The "exciter" voltage, and the main solenoid contacts. You should get 12Vdc (approx) across the solenoid coil, and 0Vdc across the "main" contacts. It is a simple test to see if your solenoid is doing it's thing. Anyone else, please jump right in.:waving:
     
  3. khouse

    khouse LawnSite Bronze Member
    Posts: 1,465

    use a known good battery for your bench tests.
    if the starters are not working after mounting them then look for a bad or loose ground or bad or loose battery connections and perform a load test on the battery. also change out the battery with a known good one. post back with your findings for more help.
     
  4. tomo

    tomo LawnSite Senior Member
    Posts: 660

    Hello, this is what i have discovered1/
    1/good battery should put out 300 amps at 10volts ,many batts only put out 200amp at 10volts difference between makers. strs willdraw 250-325 amps.
    2/it appears nippon str is only suitable 4 the smaller engines/ solenoid appears to be of poor quality/underrated-contacts burn easily and are very small not adjustable or replaceable.
    3/bendix drive one way brg seemed to fail also
    4/u can hook up time delay relay onto an additional aux contacts set instead of original setup or convert to delco str.
    5/check charge voltage on batt post while engine at half throttle,14volts and above no more than15. volts full throttle
    6/voltage drop is usually present across OEM ignition switch, typically charge runs thru the switch contacts
    7/siginal wire to solenoid is at least 10 volts while cranking ,relay is fitted to system to enable this .
    8/check elec conectors , they do corrode [voltage drop,pass limited amperage]
    9/check main fuse holder/curcuit breaker above transaxle
    for good conection
    10/check earths EVERYWHERE bat to chassis, bat to dashboard ,regulator has a small earth wire to tin plate
    11/Install additional earth bat to closure plate on engine[timing cover]
    12/check wiring diagram particlarly if its 4 your walker, there are changes over the years even in the same model.
    13/str mtr nippon denso, solenoid is not stroking far enough to engage contacts properly. This also happened to my self[as per your problem]
    14/although it is generally preferred to have nippon str usually very good ,in the application of walker it performs poorly underated and solenoid issues
    15/ poor substitute is the delco str typically,, in the walker application it is the only other option.I have only approx 650 hrs on mine .
    TOMO feel free to ask more questions:waving: :waving:
     
  5. mcambrose

    mcambrose LawnSite Senior Member
    Posts: 511

    Great replies. THanks all of you. I will look at the grounding system next.
     
  6. VegetiveSteam

    VegetiveSteam LawnSite Senior Member
    Posts: 297

    Take a voltmeter set to dc volts and put the black lead literally on the negative battery post, not the battery clamp but right on the post. Next put the red lead anywhere on a non painted area of the starter. Now crank the engine over and see if you get a voltage reading from the case of the starter. If you do then you simply have a bad ground.
     
  7. tomo

    tomo LawnSite Senior Member
    Posts: 660

    Hello, i used non genuine solenoids most likely chinese made:hammerhead: and the situation arose the same as yours.The brand you used ??????? Even if guenuine Nippon str is japanese the solenoid could have been a buy in, by the nippon company. Even so it does not matter they are unserviceable BIG mistake by nippon. Other issues i have had, plunger in solenoid builds up dirt ,grime [thin layer of sticky dirt] not allowing full extension or full retraction of solenoid plunger. This dirt is difficult to clean out as plunger is not removable,sealed solenoid.If you do attempt to remove dirt you typically wash it down onto contacts[using carb cleaner etc]:cry:
    2/I had one way bearing issues in the bendix also and all the failing parts combined i gave the nippon str the:gunsfirin .
    3/It is hard to explain but the contact set in the genuine nip str is really really BAD eg the contact set does not contact properly,out of align ment and the end result contacts burn going from real tiny to microscopic at least for 300 amps any way.
    4/ essentially good charge, good earth, and a delco str
    5/if electrics r good, new oem solenoid fitted, look into bendix operation it may be sticking when it attempts to slide back and forth.[ Commutator wears where bendix mounted on shaftand also the splines.]
    6/throw out fork also wears which causes poor solenoid and bendix operation.

    TOMO
     
  8. Jman

    Jman LawnSite Member
    Posts: 217

    Attach a voltmeter to the spade (activiation) post of the solenoid. Turn the key until you get the unit to just click. When it does watch what the voltage is to the spade. If it is less than 8 volts, you have a wiring defiency in the equipment.
     
  9. fixer67

    fixer67 LawnSite Silver Member
    Posts: 2,098

    Are you runing the solenoid off the key switch or though a relay? The solenoid needs about 30 AMPS to work right and the key switch will burn out after a while because it is not make to handle that much current. Walker now have a relay and have a relay up grade kit for older machines. In fact I had just the Walker up grade relay kit on other machines using this starter. I will get you the part number for the Walker relay kit Monday when I get to work.
     

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