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Kinda O/T... Anyone know about WWII era magnetos?

Discussion in 'The Hokey Ass Message Board' started by CJ Steak, Jan 7, 2010.

  1. CJ Steak
    Joined: Sep 23, 2008
    Posts: 1,377

    CJ Steak
    Member
    from Texas

    When I was 10 years old, an old friend of my father's gave me a WWII Homelite aircraft use generator. I'm not sure if it served on board a bomber as an APU, or was in the back of a Jeep for flight line jump start duty...

    Anyway, after 15 years I drug it out of the barn and got the piston freed up. The piston and cylinder look to be in really good shape. I've since sealed up the "jug". It gets and holds 30 pounds of pressure with me turning it over with vise grips, once chug at a time.

    Two questions.

    1. Is 30psi enough compression to fire? It's a 2 stroke.

    2. How fast does the thing have to be turning over before the magneto produces spark? I pulled the magneto cover off and cleaned/gapped the points to spec (.020). Still no sparky sparky... BUT i'm turning it over with some vise grips gingerly placed on the crank nut. Maybe i'm not turning it over fast enough to generate spark?

    If I can get this sucker to spark, I should be able to get it fired up today or tomorrow.

    I'm pretty excited! I hear these bastards are ear splitting loud when they fire off, and they run at something like 3000+ RPM? The neighbors are going to love me...

    To make a boring thread a little more entertaining, here's what the thing looks like for the most part. Mine seems to be the model below this one. I don't have the sweet blow torch for heating the jug, and I have a few less gauges. Mine is identical to the one in this post: http://www.smokstak.com/forum/showthread.php?t=16084

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  2. dana barlow
    Joined: May 30, 2006
    Posts: 5,115

    dana barlow
    Member
    from Miami Fla.
    1. Y-blocks

    Looks to be about the samething as a lawnmower,so it should spark when pulled with rope start.
    30PSI at visegrip speed should be more and a nuf psi at rope pull speed to fire off if it'
    s making spark..
     
  3. CJ Steak
    Joined: Sep 23, 2008
    Posts: 1,377

    CJ Steak
    Member
    from Texas

    Thanks Dana. I'm going to put a rope on this thing and see what happens. I figured I was turning it too slow.
     
  4. agreed , turning the motor over with a vicegrips probably wouldn't give you an accurate reading. using a rope pull , how does the compression feel? it should give you a fair amount of resistance

    same thing on the spark , you have to turn it over rather fast....use a rope with a handle with the spark plug out and you should be able to spin it fast. check to make sure the primary side of the coil isn't grounded... that's how you shut off the ignition.

    the magneto on my old Wisconsin V-4 had an impulse coupler on it to give good spark while using the hand crank...i doubt your magneto has one
     

  5. slefain
    Joined: Apr 6, 2009
    Posts: 229

    slefain
    Member
    from Atlanta

    Blow torch?
     
  6. Django
    Joined: Nov 15, 2002
    Posts: 10,198

    Django
    Member
    from Chicago

    That looks to be the same type used on B-17s and B-24s. The B-29 A.P.U. was a bit different. Pretty cool!
     
  7. llonning
    Joined: Nov 17, 2007
    Posts: 681

    llonning
    Member

    On most small engines you should be able to make/break contact on the points and get a spark. I do it all the time on B/S, Tecumseh and Kohler points style mags. You do have to be very careful on crap on the points. Just a little bit of corrosion,oil, whatever is not acceptable.

    By the way, that is how Homelite got their name, from those little generators. They have an interesting history.
     
  8. CJ Steak
    Joined: Sep 23, 2008
    Posts: 1,377

    CJ Steak
    Member
    from Texas

    Thanks for all the advice guys. I yanked a plug, clamped it to the steel frame to make a good ground and yanked on the rope... no spark.

    With the spark plug in, this thing has higher compression than I thought. I'm no lightweight... but this thing is pretty hard to yank from the compression stroke. Much harder than a weedeater or lawnmower. I can picture this thing pissing me off after about the 5th yank. Wait... i'm already on the 150th... @#$%$^$^

    Also forgot that the rope comes off the spool after the last yank.. I about knocked myself in the face.... bastard.

    I wish there was a way I could crank this thing over while putting a voltmeter on the magneto output. The mag cover hides everything though. I'm going to have to fab up an adapter so I can turn this thing over with the cover off, and with my power drill. This rope pull stuff isn't fun when you're trying to diagnose spark issues...
     
  9. CJ Steak
    Joined: Sep 23, 2008
    Posts: 1,377

    CJ Steak
    Member
    from Texas

    Yeah, it was a WTF moment for me too. Then I thought... if you're at 20,000+ feet up in an unpressurized bomber... it's gotta be pretty cold up there. They used the blow torch to heat up the cylinder so the little bastard would start. :D
     
  10. CJ Steak
    Joined: Sep 23, 2008
    Posts: 1,377

    CJ Steak
    Member
    from Texas


    When I started tearing into this thing, I scoured eBay for any information or spare parts and came across this poster I just couldn't pass up. I'm looking forward to framing it and hanging it above the generator in my garage.

    http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=320466086585&ssPageName=STRK:MEWNX:IT
     
  11. llonning
    Joined: Nov 17, 2007
    Posts: 681

    llonning
    Member

    CJ, can you get a pic of the ign setup?? I have always worked better on things if I can see them. Might have some pointers for you. I also have some access for mag parts on these things. Kind of limited though.

    Len
     
  12. CJ Steak
    Joined: Sep 23, 2008
    Posts: 1,377

    CJ Steak
    Member
    from Texas


    Len, hopefully these pics will help. It seems about as basic as it gets in there. The black wire I have in there is plugged directly into the hot side of the magneto... I still didn't get anything out of it. Even when pulling as fast as I could with the string. Eventhough it's still filthy in there, the points are clean and the "brush" surfaces of the mag and counter weight (?) in the cover were lightly polished with a scotch brite pad.

    Do mags just go bad?

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    Last edited: Jan 7, 2010
  13. llonning
    Joined: Nov 17, 2007
    Posts: 681

    llonning
    Member

    CJ, Might take a while to go through my books. I have some OLD books. This, of the top, looks similar to a Tecumseh system, but not entirely. It looks like 2 condensers?
    Also, I don't see where the plug wire comes out of the coil. If it is the black wire, it doesn't seem like it would work.

    I'll see if I can print a pic and compare to my books.

    Get back to you ASAP.

    Len
     
  14. llonning
    Joined: Nov 17, 2007
    Posts: 681

    llonning
    Member

    CJ, I can't see the number on the flywheel. With it in your hand in the pic, the FW number is what will help.

    Thanks, Len

    And, yes, they can just go bad. Usually the coil.
     
  15. Those condensers don't look very nice. Electrically isolate them and check them with an ohm meter. When you put the meter on them, they should read zero ohms and then quickly go to infinity (open circuit). If they don't read as an open circuit after a few seconds, they are junk and will stop the whole thing from working.
     
  16. CJ Steak
    Joined: Sep 23, 2008
    Posts: 1,377

    CJ Steak
    Member
    from Texas

    Len, . Unfortunately it looks like the flywheel has been in contact with the case and has rubbed the FW number off. The only number I can vagely see is a 0. Not much help there.

    Some other numbers are the serial number, 54256, P4670 in raised lettering on the inside of the flywheel, U.S. Patent 2 101 392, patented in Canada 1938. Produced by WICO Electric Company.

    Is there anything else that might help?

    Four-Thirteen - as soon as I find my meter i'll give that a shot. Sounds like a good test to perform. The wiring on the bottom condenser has almost no covering left on it and looks like it may have rubbed the inside of the flywheel. Probably not a good thing.
     
  17. CJ Steak
    Joined: Sep 23, 2008
    Posts: 1,377

    CJ Steak
    Member
    from Texas

    Oh, and the spark plug wire curved to the right and attached to the tiny brass terminal you see sticking out of the mag itself. You can see it best in pic#4. The black wire that's on it now is connected to the positive output on the mag. I just wanted to see if I could get a spark directly out of that, by passing the points.
     
  18. llonning
    Joined: Nov 17, 2007
    Posts: 681

    llonning
    Member

    OK, Ihave found 17 genset models. Some of them use 2 different mag systems. Is there a model number for the genset? A couple of the numbers are; 19,24A,24D28-2,32A120/208, etc. Don't ignore any combo of numbers, it could be anything.

    Also Prestolite and Wico are the same as for parts. It is just figuring out what it is.

    Have I told I hate mags???? (ha,ha,ha)


    Edit; I think the thing that is throwing me is the 2 condensers. Nothing shows 2 of them. I'll look through the IPL for a points match though.
     
    Last edited: Jan 7, 2010
  19. Okie Pete
    Joined: Oct 29, 2008
    Posts: 4,968

    Okie Pete
    ALLIANCE MEMBER

    What you have is called a flywheel type magneto just like a lawnmower .Looks like someone has modified the ignition. The orignal plug wire would have been a shielded type as would have been the spark plug. It looks to have been converted to a cvilian type plug and wire which will work just fine. I have a old small engine tune up book some where when i find it i will send you any info that might help. The coil and condenser look bad . The coil has tar leaking out of it not a good sign . A friend of mine bought one of those still in the wooden box he hasnt fired it up because it is NOS .
     
    Last edited: Jan 7, 2010
  20. lincolnolli
    Joined: Dec 1, 2008
    Posts: 90

    lincolnolli
    Member
    from Germany

    Hey,thats exactly what we had on our 50cc 2 stroke bikes,back in teenage times!
    It works like this:
    The coil to the right delivers 6volts,driven by the magnet on the wheel.
    This goes to the points and from there outside to a ignition coil.
    The condensor goes from points to ground.The above comment is good.
    Disconnect the condensor and try again,as they are bad 99 out of 100times when too old!

    I would look first if the coil delivers enough voltage.Maybe wire it to a small
    6v bulb and turn the "wheel" real fast.
    They actually used the lil coil for light on the little bikes.Well,kind of...
    10watts in front,4 out back..LOL..

    Then check the points,if they do both modes.I mean zero ohms and totally open.
    Last try different,well known 6V coils.

    That should bring you there.

    Damn,i like that 2 stroke stuff.Brings back a lot of memories..

    cool find!!
    Ollie:D
     
  21. JohnEvans
    Joined: Apr 13, 2008
    Posts: 4,883

    JohnEvans
    Member
    from Phoenix AZ

    That is a basic flywheel mag. The black thing is the spark coil !! ,no external coil used. As said before the condensors look real iffy. Where you have the small black wire connected will if grounded work as a kill switch. The points MUST be spotlessly clean . Point gap somewhere in the .012-.016 area. Use a NEW plug for all tests as a fouled one can look fine but be shorted out. Vist a small engine-lawnmower shop ,they most likely will have usualble ing. parts.
     
  22. hell CJ...new we had something in common...have one two - put it has a weird spark plug made out of glass...it scares me...
     
  23. llonning
    Joined: Nov 17, 2007
    Posts: 681

    llonning
    Member

    CJ, where is the pivot for the points on that? I might have found a set of points!

    Too bad the coil is internal, otherwise I could set you up with an eletronic conversion for it.

    Also if the coil is bad, if there is a numbeer on it I might be able to find a coil pack for it. Pioneer, Partner, Poulan, Tecumseh, and some others used a replaceable coil pack.

    Len
     

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