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Thread: D46U Pony Starting??

  1. #1
    Join Date
    Nov 2017
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    470

    Default D46U Pony Starting??

    been tinkering with the 6U D4 all day. when i first bought it there was a 12 volt battery on it. since then i have restored the charging system and returned to a 6 volt battery. the pony started just fine on the six volt and life was good. but now the darn thing will start with the rope second pull but it wont start with the electric starter. it seems to be spinning fast enough or at least not any slower than it used to and the battery is the correct size. what do you think??? mag impulse???
    D4 6U,1943 D4 2T,Laplant Choate C41 Carrimor Scraper

  2. #2
    Join Date
    Dec 2018
    Location
    Minnesota
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    Sounds like weak spark. As an experiment, reduce your spark plug gap down to about .015" or so and see if it starts with electric starter. I'd guess that the spec is probably closer to .020" plug gap but you don't want to run much wider than that with a magneto. Resistor plugs, resistor wires and connections on the secondary side can all come into play with hard starting. If your plugs are dirty, put them in a pan and cook them on your stove in vinegar for a while. It works great.

    Could be corroded points, bad condenser, partially failed magneto coil or weak magnets. When you are rope starting, you are probably turning it over TDC faster than your starter giving the mag just enough to fire off the cylinders.

  3. #3
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    Nov 2017
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    yea i need to pull the plugs. probably new wires plugs etc would be good. please explain cooking the plugs in vinegar? do i immerse the whole plug in the solution or just the tip? do i boil the vinegar or just get it hot?
    Last edited by bursitis; 04-14-2019 at 06:03 PM.
    D4 6U,1943 D4 2T,Laplant Choate C41 Carrimor Scraper

  4. #4
    Join Date
    Nov 2006
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    McBEE, SC
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    2,378

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    There is no impulse on that magneto, and what, you say vinegar? I will have to try that one day
    D2 5u & 3J
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  5. #5
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    Dec 2018
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    Minnesota
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    There are probably lots of ways to clean plugs. I remember cleaning plugs when I was young by boiling them in vinegar for about 30 minutes. I haven't done it in years, but I remember it working pretty well.

    Remember when repair shops had those spark plug cleaners that would sandblast the plugs? Eeek!

  6. #6
    Join Date
    Nov 2006
    Location
    Pittsford NY
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    Use solid core plug wires. I got a set of wires from Brillman as I could order them on the net and they came with boots, tips, etc. $20 I think?
    Cheers,
    Neil.

  7. #7
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    Mar 2015
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    north idaho
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    I hate the smell of vinegar and for a couple bucks a piece just buy some new ones

  8. #8
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    Moriches NY, Hancock Ma
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    Quote Originally Posted by Oldcarman View Post
    There are probably lots of ways to clean plugs. I remember cleaning plugs when I was young by boiling them in vinegar for about 30 minutes. I haven't done it in years, but I remember it working pretty well.

    Remember when repair shops had those spark plug cleaners that would sandblast the plugs? Eeek!
    That was one of my jobs in my fathers shop--cleaning and regapping plugs. we had this big old spark plug cleaner, and also had a pressurized spark plug tester.
    you can still by spark plug blasters--Hf has one for $15

    this was when i was around 8 years old, my other jobs were pumping gas, grease jobs and oil changes, spraying suspensions with penetrating oil, tube hot patches and riveting brake linings
    Cat 941B, Cat D2 4U, Cat D3B, Cat D4 7U, Cat D6 9U

  9. #9
    Join Date
    Nov 2017
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    put a set of NGK AB-6 plugs in the pony today. she starts on the second rotation now. i messed up one of the plug wires though. i jurry rigged it for now but i need a new set of wires. suggestions???
    D4 6U,1943 D4 2T,Laplant Choate C41 Carrimor Scraper

  10. #10
    Join Date
    Jan 2007
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    Moriches NY, Hancock Ma
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    I ordered the same ones Neil suggested

    https://brillman.com/product/caterpi...plug-wire-set/
    Cat 941B, Cat D2 4U, Cat D3B, Cat D4 7U, Cat D6 9U

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