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Scag zero turn w/ no spark!???!!??

Discussion in 'Mechanic and Repair' started by Phlex311, Mar 9, 2006.

  1. Phlex311

    Phlex311 LawnSite Member
    Messages: 5

    I have a first model Scag zero turn rider. Kohler engine. Last cut of last year i was in the middle of a pass and she just cut down to half power. Still ran good just half power. Like i had the throttle half way. Just started it back up with new plugs started right up and runs great but same thing only half power. Figured out by feeling how hot the plugs were that im only getting spark on one side. Any suggestions? I really cant afford to take it to the shop, id like to fix it on my own. Any advice would help!!

    Thanks so much!!
  2. Restrorob

    Restrorob LawnSite Fanatic
    Messages: 11,029

    If you have no spark on one cylinder remove the flywheel cover then remove the small kill wire lead on the affected coil. Then remove the plug and put it back in the wire boot and hold the plug casing (metal part) to one of the valve cover screws and crank the engine over while watching for spark. Remove the wire from the other plug to prevent the engine from starting up before testing. If no spark is seen then replace the coil. If this engine is equipped with the SAM smart box ignition system Kohler recommends replacing both coils as a pair. A engine model and spec. number posted would be helpful.

    Good Luck
  3. Phlex311

    Phlex311 LawnSite Member
    Messages: 5

    Tried sending you a private mess but wouldnt let me. But anyway, thanks for your reply. I have some numbers for ya.
    Model # is either cv299 or cv229. Can really tell.
    Spec # 67509
    Serial # 2400616397

    I really appreciate your help so far. I hate to keep asking but when ever you got a free min could you give alil more detailed discription on what you have already told me to try!? They guy at the local shop did mention the coil and the smart coil thing. But could you discribe in more detail what things look like such as flywheel, coil, and anything else i might need to take apart or repair. Only becasue i dont know what they are called just by lookin at them. Once i know what im lookin for i can fix it. Thanks so much for any thing else you can help me with. But like i said before. If im sittin in the seat the left side spark plug was cool and the right side was hot so there fore i figured i wasnt getting spark or whatever on that side! thanks

  4. thecrankshaft

    thecrankshaft LawnSite Member
    Messages: 172

    Hey Phlex,

    Your engine model is a CV22S (Command series, vertical crankshaft, 22 HP, electric start-from the model number). Your engine does have the speed advance module (SAM) that advances ignition timing at higher engine speeds. This system includes the extra SAM module compared to other ignition systems.

    First off, I would check for spark on the cylinder with the cool spark plug, just to be sure. Follow RestroRob's method, but keep in mind spark in much easier achieved at atmospheric pressure than it is under compression like it is in the engine. That is why spark testers are nice.

    Basically, the SAM may be bad, or the ignition module may be bad. There is a Kohler Tool to test the SAM. The problem will not be with the "kill" wire to the SAM, as this would shut down both ignition modules.

    Check the connections to the module - they should be pink and brown or yellow and brown - there were other colors used. Assuming the armature air gap is correct (gap between flywheel magnet and ignition module), I would remove the module and check the resistance as seen on page 8.10 of the service manual. In fact, there is a nice troubleshooting section in the service manual for this engine on page 8.6-8.12.

    Service Manual http://www.kohlerengines.com/common/resources/tp_2450_b.pdf

    By the way, ignition modules have a habit of showing their failure when it gets hot because the many small windings in the coil expand to the point that they no longer make contact. As for the running but with only half power, this is a good point as these engines do run quite well on one cylinder - sometimes it is hard to tell.

    I haven't heard of replacing the modules as a pair. I wouldn't do it just because they cost around $40.

    Let us know what you find!

    Good luck!
  5. Restrorob

    Restrorob LawnSite Fanatic
    Messages: 11,029

    One can do as they like, But below is what Kohler says about replacing both Modules (Coils).

    Attached Files:

  6. Phlex311

    Phlex311 LawnSite Member
    Messages: 5

    Thanks guys but i hate to say that im seriosuly still confused! I know i know! sorry! But i think im just gonna skip the head ache take the hit and take it to the shop to find out what truely wrong. Then hopefully if i dont know how to fix it you guys can help! Restrorob thanks for the links but they didnt work. It was my comp. Just wouldnt open them! Thanks though!
  7. Restrorob

    Restrorob LawnSite Fanatic
    Messages: 11,029

    In any event let us know what they find.....

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