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Testing the charging system-Kohler engine

Discussion in 'Mechanic and Repair' started by macguy59, Mar 13, 2012.

  1. macguy59

    macguy59 LawnSite Member
    Messages: 23

    I have a residential Toro ZTR Z5000. It has a Kohler Courage 21 HP single cylinder engine. The charging system uses a stator and a rectifier/regulator. Battery is not being charged. Bought new battery to be safe. Still not charging. Wiring is a 3 wire flat with the 2 outside wires being the AC Voltage coming from stator and middle wire is for battery voltage. With the stator leads disconnected from the R/R and engine at full throttle I get 42 VAC across stator leads. With just the key in the ON position I get 12.43 VDC from the center wire which I think tells me there are no breaks in the wiring between the R/R and the battery. With the engine at full throttle the voltage at the battery BARELY increases by .05 volts. With the tractor at full throttle and stator connected to the R/R I only read 12.43 VDC from the center post of the R/R to the battery (neg post to R/R). What am I missing ? The stator seems to be putting out the correct about of VAC but it's not charging the battery. (update) Put a new R/R on and the results are the same :cry: Is there something else I should be checking or measuring ? Thought I read something about the stator being shorted to ground ? How do I test for that ? Thank you
  2. ricky86

    ricky86 LawnSite Silver Member
    Messages: 2,122

    assumingStart the engine, install your leads for a amp test (leads in series on positive cable and post). Take a reading. Then engage the clutch. Clutch will draw approx 3 amps. If your reading stays the same, the charging system has to be working. Point of test is to put some kind of load on system. All assuming your meter can handle 15-20amps
  3. macguy59

    macguy59 LawnSite Member
    Messages: 23

    Thanks for the reply. What are you calling post ? Is it neg post on the battery or the center wire in the R/R ?
    Posted via Mobile Device
  4. piston slapper

    piston slapper LawnSite Platinum Member
    Messages: 4,335

    Make sure the regulator is grounded......It wont operate if it not grounded , either by a screw or a wire to something metal.
    Check for continuity between the stator wires and the engine block....should have none.
    If all else checks good....you may have a bad regulator.
    The outer wires are the stator wires...the middlle wire is positive from the key.
  5. piston slapper

    piston slapper LawnSite Platinum Member
    Messages: 4,335

    The easiest way to check to see if the charging system is working is to clip an Amprobe over the Pos battery cable or the wire going to the regulator....
    No fancy hookups ....Works every time....
  6. macguy59

    macguy59 LawnSite Member
    Messages: 23

    Thanks for all of the help. My problem ended up being 2 fold. It was a combination of a wiring issue and a bad regulator. Once those were taken care of I'm now getting 14.2 VDC at full throttle to the battery :)
    Posted via Mobile Device
  7. Robsdad0312

    Robsdad0312 LawnSite Member
    Messages: 1

    I am having the exact same issue. What was the other wiring issue. I am getting 42vac and only 12.5 at the battery and I installed a new regulator. Same thing. It is bolted to the engine itself. Should be a good ground. I am going to try and add another ground. But I'm running out of options. Thank you

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