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Magneto Woes #2

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  • Magneto Woes #2

    Believe it or not I'm still having trouble with my Wico model xh magneto that I first mentioned here in 2009! I tried the ideas then offered but haven't had any significant improvement. Basically I have a Bobcat 500 powered by a Kohler K662 engine running on propane. I keep the bobcat now in a dry pole barn but when it comes to starting it never starts the first time but only after repeated attempts. I sprayed some electrical contact cleaner in the inspection window hole and after a while it started! But when I went to start it again it just won't start. I was wondering if I could change to a battery ignition system or possibly a pointless induction system but don't have the experience to go further. ANY SUGGESTIONS? Thanks Paul

  • #2
    Certainly you can

    Assuming you can isolate the points and condenser, yes. If this is a multi-cylinder engine than you will need to modify the magneto to bring the high tension side of the external coil to the center button of the distributor part of the magneto. I did this to a Wico magneto on a 4 cylinder Waukeshau engine.

    Most magnetos have grounding terminal that comes through the front cover (cap). You can use this to complete the connection from the battery to the coil and to the points in the magneto. I removed the internal coil from the magento and wired in an external coil. It made the engine start and run ever so much better.


    • #3
      if you don't use that bobcat often will be stale petrol.

      basically the volatiles evaporate from the petrol leaving you with hard to ignite petrol .

      it will run. if you use the "ether based" engine starter spray spray the stuff directly into the intake ..when it cools down will be hard to start again.

      all the best..markj


      • #4
        What may not be 110 percent obvious on those old magnetoes, and is often left out in rebuilds, is a gasket on the magneto cover which prevents point corrosion.l I had a similar problem with a Wisconsin Magneto that took years to figure out because the previous owner had left the gasket off. It was a nice tight fit, and did not appear to need a gasket. It would always start eventually after the points got a little friction, but cince I got the right gasket on it's been many times better. F-M and Wico are nearly identical, and both require a gasket.


        • #5
          I have learned to predry my magneto with a 60w light bulb the day before 'IF' it has been cold and followed by rain or other forms of humidity even though my caterpillar is in under cover. Lots of cold metal in those machines makes condensation. It takes next to nothing to foul up my magneto. It doesn't take freezing just cold followed by moisture/humidity. The heat from the bulb is all it takes. I also try to run mine for 1 hr about once a month just to heat it up - and this does wonders as condensation is cumulative - the longer it sits the more water you end up with.


          • #6
            You didn't put your location in your profile, so we don't know where you're located. If you're close to either CoolSpring, PA, or to Portland, IN, just bring the mag to Magneto Mark and he'll fix it at the show. CoolSpring is coming up in June, Portland is in August. You could probably ship the mag to him if you wanted to.

            Mark is actually located in Colchester, CT, his number is 860-537-0376. I have no connection to him, just a satisfied customer.


            • #7
              I wanted to add to my thread that the Kohler K662 engine is an air cooled twin cylinder engine and the magneto has a distributor type cap with two spark plug leads. Thanks for the replies. Paul


              • #8
                I'd find another mag that tested good & replace. I know it's not the answer you were looking for but I like things to start as they should.
                "Let me recommend the best medicine in the
                world: a long journey, at a mild season, through a pleasant
                country, in easy stages."
                ~ James Madison


                • #9
                  Are you sure it's not the propane system? I have had many vehicles that run on propane. After sitting a couple days, you have to use a primer button, otherwise, it would start on 2nd or 3rd try.


                  • #10

                    I don't recall what you did earlier, but in my experience with ignition - concentrate on the low voltage side first as it is much more critical than the high tension, in particular check the points.

                    I don't like the sound of spraying anything in there (if that is what you mean).

                    I am assuming you already have the points in good order with the gap set, but I would still give them a quick check and clean - open the points with a small screwdriver so you can see if they look ok, i.e. flat, unburnt faces. If good, give them a quick clean as follows: Make sure the points are closed, then make a narrow strip of say 400 wet & dry paper folded over, open points with finger and put the paper between them, let points close, pull strip out, repeat a few times. This will give good contact surfaces. If there is room, use a feeler gauge with the wet & dry paper folded over it, work it in a out a few times.

                    Vital to then clean the points, use gasolene soaked rag and repeat above so points are spotless with no chance of any sand paper dust etc. remaining.

                    Apologies if this sounds too basic, but I don't know what you have or have not tried, and it's what I would do first.


                    • #11
                      Originally posted by jb-mck
                      Are you sure it's not the propane system? I have had many vehicles that run on propane. After sitting a couple days, you have to use a primer button, otherwise, it would start on 2nd or 3rd try.
                      propane !!! ......i should have read it properly .

                      so don't know what you have there ..

                      the ignition system on propane is crucial has to be up to the mark ..

                      propane is an insulator ..and its hard for the spark to jump the gap would rather go to earth at any opportunity ..

                      so ht leads .......and all components have to be up to only have to have a bit of damp in the ignition system, when running on propane ..and it acts 10 times worse than on petrol
                      ..been running my cars on propane for over twelve years ..

                      all the best.markj
                      Last edited by aboard_epsilon; 05-23-2012, 08:57 AM.