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Kohler 26 running rough

Discussion in 'Mechanic and Repair' started by r6wild, Dec 13, 2005.

  1. flman

    flman LawnSite Member
    Posts: 26

    Hope this can help. Since you stated that you tried everything as far as carburetion goes here is a few things to check out on that stubborn miss.Not in any certain order.
    1. Check for leaking intake manifold gaskets,you can see them pushed out visually.
    2.Have a tech put a test on the SAM(SPARK ADVANCE MODULE)this will cause ignition problems which will make the engine act as if a coil is bad.
    3.Take your plug gap to .025
    4.Pop the valve covers just to make sure all is well

    Hope this helps!
     
  2. r6wild

    r6wild LawnSite Member
    Posts: 12

    Figured out the engine is running on one cylinder. Can anyone help me figure out if it could be the Rectifier-Regulator, Module ignition or the Module Speed Advance. Any help would be appreciated.
     
  3. r6wild

    r6wild LawnSite Member
    Posts: 12

    Let me also say that when I pull the plug from the cylinder thats acting up it runs smooth but it is running on one cylinder. When I put the plug wire back on the plug it starts to run bad and back fire.
     
  4. Redneckn

    Redneckn LawnSite Senior Member
    Posts: 294


    I can say that it will not be the reg/rect as that is part of the charging system and has nothing whatsoever to do with the "firing". It could be the module or the SAM. I would have the SAM tested.

    To test the Module: Point 1 is the little spade tab, point 2 is the larger spade tab, point 3 is the plug wire (inside the boot), point 4 is at the holes for the mounting bolts.

    From point 1 to point 4 with your multi-meter set to read Ohms, you should have 945-1175Ohms.
    From Point 2 to 4, should have 149-166 Ohms.
    From point 3 to 4, should have 3750-7000 Ohms.

    If yours tests within those specs, the module should be fine.
    Double check your spark plug. May even swap the plugs to see if the "bad" side starts to run normal. If you are certain about the plug, nothing changes with plugs reversed, and the Module checks within the specs I gave. The SAM would be the issue. The red wire going to the same. When the key is in the "on" position, make sure that red wire has at least 8vdc on it. Really, it needs to have whatever your battery voltage is. If it does not, that would be the issue. But I dont think the voltage to the SAM is the problem because it will start and run. I dont know a way to test that think with a SAM tester.

    Good luck.
     
  5. lawnmaniac883

    lawnmaniac883 LawnSite Silver Member
    Posts: 2,613

    Is it possible he sheared the flywheel key?
     
  6. John Gamba

    John Gamba LawnSite Fanatic
    from ct
    Posts: 10,812


    Or i could be almost sheared off????
     
  7. Redneckn

    Redneckn LawnSite Senior Member
    Posts: 294

    That is something to check but I would doubt that to be the issue. The flywheel key on a Kohler isnt like a Briggs. It's a beast of a key to start with. Plus, you generally will run into the situation where if the key is sheared (even partially) that it wont run at all.

    But again, it is something to think about and to check as well as everything else. Mainly because on small engines, you can get so involved in the big complicated things that can go wrong, it's easy to overlook the the little simple things... *like being out of gas*:eek:
     
  8. r6wild

    r6wild LawnSite Member
    Posts: 12

    Thanks for the help I will test the module tomorrow and post the verdict.
     
  9. JHugh

    JHugh LawnSite Member
    Posts: 84

    I would remove the valve covers and check the rocker arms. I have seen a few 25 Kohlers with the same mentioned problems have the rocker arm stud retaining bolts back out of the head. The valves are working but not opening up all the way.
     
  10. r6wild

    r6wild LawnSite Member
    Posts: 12

    Problem solved, a wire coming from the smart box to the coil had a loose connection, at the coil. Thanks for all the help. Wish I would have checked that before I bought the new carb.
     

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