Kohler 20 hp engine question.

Discussion in 'Mechanic and Repair' started by ts923, May 10, 2008.

  1. ts923

    ts923 LawnSite Member
    Messages: 15

    I originally posted this question in the Homeowner's Assistance forum, but was directed by another member to post it here as I would get better results.
    Hello all, Brand new to forum, glad I found it! I have an Ariens GT20 I bought back in '98 for my 6 acre lot ( 3 1/2 + and increasing each year of mowable area ). I'm having an issue this year getting it started and my lawn is growing very fast m ( haven't cut it yet ) I thought it might had been the battery so it was replaced ( under warranty no cost.) Then I heard a Clicking sound when I turned the key so I replaced the solenoid, not the fix. I then figured it might be the ignition switch, (working on troubleshooting that now.) In the meantime I am able to turn the engine over by jumping the solenoid with the positive cable from the battery. It will crank over just fine but won't start. Upon further looking into this I noticed it's getting gas but no spark. Here is my dilemma. It is hard to access the ignition coil on this unit. It is behind a couple of access panels. I went to Ariens site and looked at a parts blowup and they don't even show the coil. I even did a web search to no avail. Does this model even have a coil? If not how does the spark get generated? I followed the spark plug wires (2) to the panel, so I'm thinking it's located behind that. Any help would be appreciated. It is an Ariens GT20 garden tractor with a 60'' deck and a Kohler 20 hp engine (twin cylinder). Thank you.
    Edit: It is an M20S engine /spec 49533 ser # 2413014576 and the Ariens tractor model is a 931034
  2. Sharpcut 1

    Sharpcut 1 LawnSite Senior Member
    Messages: 452

    Make sure key is in "on" position, or you can crank till you're blue in the face and not have any spark. Both cylinders going at once is pretty rare. probably a safety issue, especially with no crank. If you can isolate the kill wire out of the harness (Unplug it) and crank over andhave spark, it's a key or safety issue.
  3. ts923

    ts923 LawnSite Member
    Messages: 15

    I don't have the electrical schematics for this tractor. Is there an easy way to locate the kill wire in the harness to disconnect? I know there are 2 safety type switches on this tractor, one in the seat that shuts the engine down if the blades are engaged and you get off the seat, otherwise I have been able to start the unit in past years without sitting down. The other one is located next to the "gear lever" (which slides forward to go faster, backward to reverse.) There is a "notch" where you are supposed to place the lever when you go to start the tractor, and if I put my finger in the slot I can feel a rubber flipper which I believe the lever must contact to be able to start the tractor. I will look at the online parts breeakdown and my tractor to follow the wires from these switches and try to locate the kill wire. Thank you.

    FIXDISS LawnSite Senior Member
    Messages: 445

    On my mv-18s there is a harness just in front of the oil filter that has a connector there which has 2 wires going up toward the underside of fan shroud. the white wire is the kill wire. You may need to connect a jumper from the purple wire to the purple/black connector of the plug but leave white one off. Spin engine over to see if it starts or fires.If it starts up you can only shut it down by grounding the white wire or pulling both plug wires . Hope this helps.
  5. Bill Kapaun

    Bill Kapaun LawnSite Senior Member
    Messages: 956

    Here's a link to the engine service manual.

    Most likely, you'll have 3 wires going up under the engine shroud. 2 should be from the alternator and be the same color.
    The 3rd should be the kill wire.
    Keep in mind that sometimes a mouse can get in there and eat the insulation, shorting the wire. It happens much more frequently than one would expect.
    Anyway unplug it and see what happens. If still no start, use a volt ohm meter and check the free end to engine ground. IF 0 Ohms, it's shorted under the shroud.
  6. GravelyNut

    GravelyNut LawnSite Bronze Member
    Messages: 1,594

  7. ts923

    ts923 LawnSite Member
    Messages: 15

    UPDATE: I found a connector coming from the back of the tractor to the front, and I unplugged it. (There were two wires on either side of the connector.) The tractor started right up and ran fine. I let it idle for awhile while I "buttoned " everything up. I got on it and drove to the edge of the lawn and set my deck height and then pulled on the lever to engage the blades, and nothing . If I keep the engine running and try to reconnect the connector the engine dies immediately. I started looking at the two safety switches that I am aware of, (I think there's only 2) and I disconnected one of the wires to the switch by the forward/reverse lever and nothing changed. I then did the other wire and still the same results. I don't even know how to disconnect the seat one as it looks difficult to access, and I don't see where I can disconnect any wires on that one. There are two black, small rubber (?) cylinders that the 2 wires that come from the switch pass through but I don't see where they can be taken apart. The wire colors are green and white. In the front the wires that come after the connector, one goes to the front of the engine and the other goes and follows along a path alongside the spark plug wires as they disappear under a plate (cover). I took the plate off between the seat and the dash and followed the harness, but I didn't see any breaks or possible areas of trouble. The wires are all taped together from the factory with electrical tape along the whole stretch. All I want and need to do at this point is to get the blades to engage so that I may cut my lawn. I can deal with the full repair after I get my lawn mowed, and order any necessary parts for repair. Is there a temporary fix to just get the blades able to work so I can cut my lawn?
  8. Bill Kapaun

    Bill Kapaun LawnSite Senior Member
    Messages: 956

    Did you TRY disconnecting the kill wire to the engine?
  9. ts923

    ts923 LawnSite Member
    Messages: 15

    After posting my last post my neighbor came over to look at it again with me. The main problem I am having now is getting the blades engaged to cut. (I can worry about why it won't start w/ the key after I cut my hayfield err, I mean lawn.) He took off the clutch switch that engages the blades on the dash and we cleaned it , that didn't do the trick. I do have a new question that might be related to this whole mess and it has to do with the volt meter. When the engine is running, shouldn't it be registering at least something or shouldn't the needle move? All through the troubleshooting process, the voltmeter has not moved at all and it makes us think that, that may be part of the problem. Yes? Another thing I noticed is that when I had the harness that comes from the rear and has the 2 wires possibly from the safety switches connected, the engine would NOT start when the ignition key was "ON" and I jumped the solenoid. After removing the switch at the speed selector and connecting the wires that went to it together, I was able to start the engine with the key "ON" and by jumping the solenoid and the harness was connected together. Although it would only run for a few seconds before stopping. I'm wondering if it's something having to do with the relay that is near the ign. switch or the clutch switch that may be bad. If I disconnected the harness from the back with the wires from the safety switches is that the same as disconnecting the kill wire to the engine?
  10. Bill Kapaun

    Bill Kapaun LawnSite Senior Member
    Messages: 956

    Most likely not since those wires may go into various other switches and/or relays.
    Disconnecting it AT the engine bypasses all that stuff!

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