magneto Neptune 0B34

[sbrown21]

I have a Neptune 0B34A that needs a Eisemann 72A magneto , does anyone know where I might get one? I have the old one but it test’s bad. I have looked on the internet , checked with Doug Penn but come up short on this one. ( need some advice ) Thanks

[RICHARD A. WHITE]

If memory serves that one can be converted to run on 2 OMC coils…..Can you post a picture to confirm?

Memory corrupted, by lack of sleep….sorry 🙁

Thanks Joe

http://www.richardsoutboardtools.com
classicomctools@gmail.com

[joecb]

That Neptune is an opposed twin, correct? If so the Eisemann mag has a "donut" shaped floating secondary coil. Unlike the opposed twin motors that have a cylindrical shaped coil you can not fit two OMC or similar coils to the armature. The only options that I know, short of finding the correct replacement coil is … buy a new coil for a Maytag model 72 twin (ebay $$$$) or perhaps retrofit a John Deere Pony motor coil (also e bay but still $$). You are up against the same problem that confronts many of us Lauson Sportwin owners.
Joe B

[jcrigan]

If you can find an Eisemann 82D that was used on earlier models, it may work with your motor. The flywheel is different on that model. Tomorrow i will look at an OB32 an an OB35 to check for compatability.

[sbrown21]

Thank you guys for the help. I didn’t know if the Maytag coil was close enough to the 72A to work , the 0B34 Neptune is an opposed twin. I will check the John Deere and see if it might work. I have heard of people rewinding and restoring a coil is this something they do on a 72A coil ?
Steve

[joecb]

I believe that the Maytag coil MAY be a direct replacement as the core size (I suspect ??) is the same as your Eisemann… double check on this before spending the $$$. As for the John Deere, I have seen the successful retro fit into the Lauson Sportwin mag which is an Eisemann 62, however the armature must be cut down to fit the coil ( I think 1/2" X 1/2")

Joe B

[stanley]

Let me state at the start,I know just enough electrical theory to install a light switch without getting shocked.Now the dumb question:Is it possible to dispense with a coil altogether and rig a motor to run off of a battery.I know some early outboards did and that when the generators on my old cars quit working that is essentially what is happening.

[jcrigan]

You could run it with an external coil and battery using only the points and condenser on the mag. Find a coil from an older 4 cylinder Honda that fires two plugs at once or two good coils will work.

[joecb]

Just in the way of entertainment I’ll relate how the "floating secondary" coil works. We discussed this at length at the coil testing seminar at Constantine this year and the topic seemed of interest. The normal coil that fires a single cylinder ( like the common OMC coils) are constructed such that the secondary (high voltage) winding has one end of the coil connected internally to ground, the other end of the winding goes to the spark plug… pretty straight forward, when the high voltage is induced those little electrons exit the coil jump the spark plug gap and scoot back to the other end of the winding via the ground path of the engine block. NOW with a floating secondary there is NO connection of the secondary windings with ground ( AKA an ungrounded secondary). These coils are used to fire opposed cylinder motors where the two cylinders fire at the same time. So how do those little electrons make it around the circuit? When the coil fires, those little guys (maybe gals too) head out of one end of the secondary winding to spark plug #1 where they jump the gap, then run through the engine block to spark plug #2 , jump that gap (in the opposite direction), then back thru the #2 spark plug wire and finally back to the other end of the secondary winding. So you see the in terms of the speed of light (or electron speed) your simultaneously firing twin is in fact not firing both plugs at the exact same time.
Hope that this helps.
Joe B

[jcrigan]

Interesting. So how do the electrons jump the first gap when there is an open circuit at the second gap?

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