Calling all Coil Experts & Jack of all trades

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This topic contains 14 replies, has 6 voices, and was last updated by Buccaneer Buccaneer 3 months ago.

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  • Buccaneer
    Buccaneer
    US Member - 1 Year
    Replies: 2992
    Topics: 835
    #171600

    I’m still trying to solve the mystery of why my coil conversion is not working out,
    trying to use a B&S coil on the Neptune’s twin, opposed cylinder, Eisemann
    laminate, while others have supposedly been successful. One person in the club
    did this, but his coil was oriented 90 degrees different than mine.
    Some Maytag fellows have done this conversion with success, while
    one said he had poor low speed spark.
    Photos attached tell some of the story.

    Did some more research, thinking and testing
    on the B&S coil conversion on the twin Neptune.

    Lots of information on Smokstak with people trying
    this conversion on their Maytags using the same
    Eismann 72 coils.

    The secondaries on the old Eismann and evidently
    the B&S coil I’m attempting to use, Smokstak is
    referring to this type as “Pass thru” secondaries,
    that is the secondary is not grounded to anything,
    and in firing a twin cylinder engine, the spark
    travels through one secondary plug wire, through
    the spark plug, through the engine block, through
    the other spark plug, and back to the coil.

    This would explain why I was having trouble testing
    the B&S coils on the Stevens tester by grounding
    one secondary to the laminate, and the other secondary
    plug wire to Stevens test lead. It would take high amps
    to fire the coil on the tester, and would start arcing
    to ground between the coil and laminate.
    Pretty sure I’ve tested Opposed, twin cylinder Johnson
    in this manner with no problems. Are those coils
    designed differently?

    I found a testing procedure in the Merctronic manual
    (have manual, but no tester) that shows testing such
    coils by hooking up one secondary to the test lead,
    and the other secondary plug wire to the Test Probe lead.
    Tried this procedure on my Stevens, and worked great
    on the B&S coil mounted on it’s original laminates,
    firing the coil stead at 1.5 amps.
    When I un-mounted the coil from it’s laminates, the
    coil would not test at all.
    When I put the B&S coil on the whittled down Eismann laminate,
    it started to fire, but not until very high amps. (around 4 amps)

    What’s the reason for the coil only firing good on it’s original
    laminates, not firing at all with no laminates, and very poor
    on the Eisman laminates?
    I presumed the Stevens was supplying voltage to the primary
    circuit and the laminates would not be needed for testing.

    I re-read all of Mohats articles on magnetos last night,
    but alas, I’m still at a loss on what’s going on!

    Ideas welcomed, brilliance greatly appreciated, lol.

    More on this saga previously posted here……

    1936 / 37 Neptune OB64A 6 hp, Opposed Twin

    Thanks!

    Prepare to be boarded!

    Attachments:
    RICHARD A. WHITE
    RICHARD A. WHITE
    US Member - 2 Years
    Replies: 1576
    Topics: 124
    #171610

    It MUST have lamination’s thru the coil or no tester will test it… Don’t ask me how I know…LOL That is how the field is created, without lams, no field..

    http://www.richardsoutboardtools.com

    Buccaneer
    Buccaneer
    US Member - 1 Year
    Replies: 2992
    Topics: 835
    #171632

    It MUST have lamination’s thru the coil or no tester will test it… Don’t ask me how I know…LOL That is how the field is created, without lams, no field..

    Richard, Guess I forgot about the part in Mohat’s article about the “iron core”.
    For some stupid reason I was thinking the Stevens was supplying
    juice to the primary, enticing the secondary to get all happy.
    Will have to keep that in mind for future testing, but that still doesn’t
    explain why my modified Eismann lams aren’t working in the
    B&S coil. Mr Tesla, where are you!
    Thanks.

    Prepare to be boarded!

    Avatar
    fleetwin
    US Member - 2 Years
    Replies: 2626
    Topics: 32
    #171634

    No Tesla here, that is for sure. I guess I would put the BS coil back on its original lamination and restest….If it performs as it did originally, then something(s) about the laminations are different…
    One thing that I am noticing is that the winding is offset by 90 degrees on your weisman lamination….And, the outer laminations are farther away from the winding also….

    Buccaneer
    Buccaneer
    US Member - 1 Year
    Replies: 2992
    Topics: 835
    #171637

    No Tesla here, that is for sure. I guess I would put the BS coil back on its original lamination and restest….If it performs as it did originally, then something(s) about the laminations are different…

    One thing that I am noticing is that the winding is offset by 90 degrees on your weisman lamination….And, the outer laminations are farther away from the winding also….

    Fleetwin, thanks for the input. I did put the B&S coil back on it’s original lams and it tested good
    on the Stevens, so the problem must have something to do with the Eisemann lamminations.
    I can’t see how the coil would care about it’s orientation on the lamination, but indeed,
    the Briggs lams are a completely different design, and for some reason, have a different
    color coating on each half.

    Prepare to be boarded!

    • This reply was modified 3 months, 1 week ago by Buccaneer Buccaneer.
    mercuryman
    mercuryman
    US Member - 1 Year
    Replies: 340
    Topics: 121
    #171643

    When I first got my Neptune OB64 I tested the coil on Merc O Tonic got no spark. They I checked with Ohm meter and results confused me. Here is how I got a spark using the tester. Connected both plug wires to plugs then put the plugs on small piece of tin and clipped jumper wire to tin one end and the other to tester ground lead. Connected red power lead to coil primary and primary ground to tester ground. They I had spark both plugs. You know some of the B & S coils have electronics and don”t need points.

    Mumbles
    Mumbles
    Canada Member - 2 Years
    Replies: 4057
    Topics: 418
    #171644

    How’s your flywheel? Maybe the magnets need a charge.

    Buccaneer
    Buccaneer
    US Member - 1 Year
    Replies: 2992
    Topics: 835
    #171647

    Thank for your replies Mercuryman and Mumbles. When I was pulling over the
    Neptune to check for spark, I had both spark plugs screwed into an aluminum bar
    that was grounded to the engine, so the circuit in the secondary was complete,
    but I only got very weak spark, sometimes none.
    I believe I have the testing procedure figured out on the Stevens for these type
    coils, and the B&S coil test good on the tester, but only when it’s in the original B&S laminates.
    The flywheel magnets seem to have decent pull, and I’ve kept a metal bar between
    the magnets whenever the flywheel has been off.
    Confusing that magnetism and electrical stuff is….. can’t
    even see the darn stuff!

    Prepare to be boarded!

    Avatar
    joecb
    US Member - 1 Year
    Replies: 339
    Topics: 58
    #171649

    An observation… the B&S laminations apparently form a magnetic flux loop around the coil. That piece of insulating paper in the lamination gap is “invisable” to the magnetic flux. The Eisermann lams do not form the same loop. Now how or if this difference is what’s causing the problem, I can’t answer. Only an observation.

    Joe B

    Looking at the photo again… try testing the coil on the Eisermann lams with the assembly laying in the flywheel so that the lams and the flywheel magnet form a loop … imitating the loop on the B&S set -up

    • This reply was modified 3 months, 1 week ago by Avatar joecb.
    Buccaneer
    Buccaneer
    US Member - 1 Year
    Replies: 2992
    Topics: 835
    #171659

    An observation… the B&S laminations apparently form a magnetic flux loop around the coil. That piece of insulating paper in the lamination gap is “invisable” to the magnetic flux. The Eisermann lams do not form the same loop. Now how or if this difference is what’s causing the problem, I can’t answer. Only an observation.

    Joe B

    Looking at the photo again… try testing the coil on the Eisermann lams with the assembly laying in the flywheel so that the lams and the flywheel magnet form a loop … imitating the loop on the B&S set -up

    Joe, interesting thoughts on the magnetic field.
    One thought I was wondering about was if the B&S coil was “polarization” sensitive
    somehow. Out of my league, lol.
    I’ll try the Stevens test you suggest……… maybe that will jump start some life into it!
    Thanks.

    Prepare to be boarded!

    Buccaneer
    Buccaneer
    US Member - 1 Year
    Replies: 2992
    Topics: 835
    #171712

    I did some more testing (as suggested, I think) of the B&S coil on the Eismann lamination,
    laying it in the flywheel next to the magnets, in two different
    positions. Next, I tested the same coil back in it’s original lamination.

    Short story, even shorter, Poor performance with the B&S coil on the Eismann lamination.

    Three short test videos, and pictures that coincide.
    Perhaps I’ll try a pony coil next 🙁

    Prepare to be boarded!

    Attachments:
    RICHARD A. WHITE
    RICHARD A. WHITE
    US Member - 2 Years
    Replies: 1576
    Topics: 124
    #171726

    I am confused as, I have never tested a coil with it touching the magnets??????
    I have owned a Mercotronic Model 98 and now have a Model 88, I do not recall seeing that in the instructions….
    It is my understanding that the testers use the battery voltage to mimic the electricity used to create the magnetic field..

    http://www.richardsoutboardtools.com

    Avatar
    joecb
    US Member - 1 Year
    Replies: 339
    Topics: 58
    #171727

    Richard, no confusion…. this was just an experiment. Read back a few posts for explanation.

    Joe B

    Mumbles
    Mumbles
    Canada Member - 2 Years
    Replies: 4057
    Topics: 418
    #171757

    A coil has to be in motion thru a magnetic field (or vice versa) to generate any electrical energy. With the flywheels magnetic field surrounding the stationary coil, it might affect what the Stevens unit is trying to do. Just a thought.

    Buccaneer
    Buccaneer
    US Member - 1 Year
    Replies: 2992
    Topics: 835
    #171761

    I should have re-emphasized that previous test with the B&S coil
    on the Eisemann lamination, testing while Not in the flywheel, were equally,
    if not more, disappointing.
    It was just an experiment to see what impact the flywheel magnets
    might have on the magnetic field and testing results.

    Most likely it’s the configuration of the B&S lamination specifically designed
    for it’s coil, that makes the magic happen at lower amps on the Steven’s tester.

    Sure wish I knew a “Magnetic Engineer”, lol.

    Prepare to be boarded!

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