Allen Scythe points gap problem

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This topic contains 7 replies, has 3 voices, and was last updated by  gseman 1 week, 4 days ago.

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  • #35378

    gseman
    Participant

    I recently acquired an Allen Scythe, 2 stroke 25c engine I think, that has not been started for years. Cleaned the carb, and tank, replaced the points, Plug, Condenser and coil, gapped the points and reset the timing after cleaning everything. Finally got it started on first pull, twice, then it stopped. Did not have the flywheel bolt tight enough…re- timed…fixed. Engine ran sweet up till this point, no issues. However, found that there is very little difference between points open and points closed to a point where, if they are gapped at 15 thou, they don’t fully close. Put a meter across them to find that I had to close them down to about 10 thou to get a points closed reading on the meter. Any one had this problem before and found a solution ? Almost sounds like the eccentricity on the points cam is worn down. Could it be anything to do with the governor ?
    Also, the magnets were intermittently fouling the coil carrier brackets very slightly scraping, so repositioned coil and backplate as far as the screws would allow, seems OK now. If anyone can assist with this, it would be very much appreciated as I am not getting a spark now at-all.
    Hope this all makes sense ?

    #35379

    wristpin
    Participant

    When it comes to Allen scythes I’m a bit out of my comfort zone but I do remember that back in the day there were two very similar sets of points that were fractionally different . The difference , if I remember correctly, was the profile / height of the nylon heal that ran on the cam. It may be totally irrelevant to your issue, but may be worth checking.

    #35380

    gseman
    Participant

    Thanks Wristpin, I’ll check it out next week as I have another set

    #35381

    wristpin
    Participant

    Thinking about your mention of the pole pieces fouling the flywheel . Could you have a combination of crank and main bearing wear allowing some lift of the crank causing both the fouling and the difficult points setting ? Grasp the flywheel and check for discernible lift. Not on an Allen Scythe, but on Suffolk four stroke engine I have seen such wear that the points could be opened and closed just by lifting the flywheel.

    Edit
    Just has a dig into a box of new old stock points and found these two with decidedly different heal profiles

    • This reply was modified 2 weeks ago by  wristpin. Reason: Image added
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    #35384

    wristpin
    Participant

    Thinking about your mention of the pole pieces fouling the flywheel . Could you have a combination of crank and main bearing wear allowing some lift of the crank causing both the fouling and the difficult points setting ? Grasp the flywheel and check for discernible lift. Not on an Allen Scythe, but on Suffolk four stroke engine I have seen such wear that the points could be opened and closed just by lifting the flywheel.

    #35388

    giw01
    Participant

    I think I set the points gap on mine @12 thou, seems to run fine at that.

    #35393

    gseman
    Participant

    Gents, thanks for your comments. Had another serious look and found that the Governor on the flywheel was partially seized. Got it all working and it seems to have cured the problem. Starts first pull now. Just need to sort the carb out now before I set to and start stripping and painting.

    #35394

    gseman
    Participant

    Couldn’t find any crank wear at-all. Hopefully, carefully positioning the back plate and the coil mountings has cured the fouling problem as well.

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