Villiers Mk25 Ignition

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  • #26709
    vhgmcbuddy
    Member

    I have read several threads on this forum regarding the thorny issue of Villiers ignition systems. While I have my Allen scythe in bits for a thorough clean and service, I have been toying with the idea of fitting an electronic ignition module (either Meco or Nova) to replace the points and condenser. I have fitted these modules on a couple of my old 60’s Pioneer chainsaws, resulting in much improved cold starting with no kickback. On closer inspection of the Villiers Mk25 (4-stroke) flywheel, the entire periphery is magnetic. Normally, for these ignition modules to work, they require a flywheel with a single magnet. Has anyone successfully fitted a Meco/Nova module to a Villiers Mk20 or 25? I think the Mk10, 12 and 15 also have a similar magneto setup, but not sure.

    Thanks

    Sean

    #26710
    hortiman
    Participant

    Try contacting Jon Cruse ( the mower centre Hailsham) he is pretty clued up on that sort of thing, and has been repairing all types of machines for many years, and sells villiers parts from all eras.
    He has a website, or call 01323 842477 weekdays.
    Hope this helps
    Chris

    #26712
    vhgmcbuddy
    Member

    He is shut on Wednesdays!

    #26775
    vhgmcbuddy
    Member

    Gday Busman, To Replace points With electronic modules,
    Disconnect wire from points(primary wire from coil) & connect to (+)Positive terminal on electronic module.
    Make a lead from the (-)Negative Terminal to the screw that you will use to earth(screw) the electronic module to frame.
    Good Luck
    Al

    #26779
    wristpin
    Participant

    Maybe I’ve been lucky, but over the years I’ve fitted dozens of Meco modules to a variety of engines including many old Villiers, and never experienced a problem – other than on one. That exception was a two-stroke Allen Scythe with the centrifugal governor system operating on the contact breaker points. Fitting the module effectively by- passes the governor, resulting in spectacular rpm! We worked out a way around the problem, but that’s another story.

    #27167
    vhgmcbuddy
    Member

    Success!! Fitted a Nova II module and now have sweet running Villiers Mk25.
    The only issue I found with the Nova module is that the spark is generated 180 degrees from the original contact breaker. The Mk25 flywheel contains two magnets, one small, one large. The original contact breaker setup had the points opening as the smaller magnet reached the 12 o’clock position. After fitting the Nova module, I set the flywheel in the same position it had been in, which produced a puff of smoke from the carburettor every time I tried to start it. This could only happen if the intake valve was open, so I knew the timing was way out. As the ignition module is triggered by a magnet passing the coil, I guessed that the module was using the larger of the two magnets, so rotated the flywheel 180 degrees. This now produced kickback when trying to start, but at least I knew the spark wasn’t far from where it needed to be. After a couple more attempts, rotating the flywheel a few degrees at a time, I found the sweet spot.
    The actual fitting of the module was very simple. There is a stud on the outside face of the armature plate which can be used to connect an engine stop wire. I connected the positive terminal of the module to this stud, as it is wired back to the coil. The negative was connected to one of the mounting studs for the fan cowling. As I had removed the whole contact breaker assembly, is used one of the now redundant mounting holes for bolting the module to the outside of the armature plate. I could have mounted the module directly in place of the contact breaker box, but was worried that it might not have enough ventilation, as they do get hot in use.

    Thanks for your input chaps.

    Sean

    #27169
    wristpin
    Participant

    Very interesting about the flywheel positioning / timing issues. As per my earlier post, I have fitted many Meco units and never experienced a similar issue but will log your work around for any future problems. It would be interesting to know the final positioning of the original Villiers timing marks with the flywheel in the position that gives satisfactory running.

    EDIT. Just occurred to me, are you referring to a Mk25, which is a four stroke, or actually to a Mk25C, two stroke?
    ,

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