Wico Type C Mag. Coil

1) The wire ends to be soldered gotta be clean all the way down to bare shiny metal and free, of course, of any insulation or oxidation or residue.

2) If theres sufficient length/slack, I suggest you loop and crimp the junction wires to add mechanical strength. If theres not enough wire exposed to do so, at least have the ends side by side where/if possible.

3) To help avoid any heat insulation damage, to the extent possible, heat sink (maybe use clamp on type tweezers) the wire where it goes to the inner coil area while still allowing the wire temp to reach good soldering capability.

4) Having the junction jigged up firm and heat sunk where possible, then tinning the wires then carefully soldering might well get you by.

5) A careful taping or otherwise securing the soldered junction to avoid stress is one last consideration.

Remember, the simple low voltage ohmmeter primary (ground to points, low ohms) and seconday (ground to side output button/terminal, high ohms) continuity checks Duane and I gave ya will tell you if a coils bad (open) or not, but even if it passes, it could still be faulty due to high voltage insulation break down failures.

Let us know how you make out, Good Luck

John T

You ask..

Quote: "I don't understand why there are 3 wires, should there be?" >>>

_Yes, Duane explained that below.. Those Wico coils have both a primary & secondary winding in them.. The primary winding runs from that ground wire set [one of the two wires going to that ring ], then through that single insulated wire exiting the coil & on to the points.. The secondary winding runs from that ground wire set to the high voltage button in the center of the coil [the one that the cap terminal touches].. When the internal magnetic rotor rotates inside the field laminations it induces a current flow in the primary winding.. Then, when the points open that current flow is quickly interrupted & the primary winding collapses.. That in turn induces a higher voltage in the secondary winding & that higher voltage [kilovolts] then passes through the spark rotor & on to the cap towers, then through the plug wires, then on to the spark plugs.. The return path from the plugs to the coil’s secondary side is through the engine block, to the governor, to the mag case, to that little ground ring & then through that second little ground wire into the coil.. That is a lot of words to say it should have those 3 wires.. Those 2 ground wires go to different places inside the coil. [one’s the primary ground & one’s the secondary ground..

JDClooney@aol.com

Your primary should read 0.52 ohms (hard to read this low unless you have a good meter), and the secondary should read about 5000 ohms, plus or minus 1000 ohms.

John has covered other testing methods.

Sooooo ooo, I cant tell for sure sitting here what you have, but the ground and points leads should be somewwhat obvious based on if bare or twins (ground lead) versus the other ones insulated (and often longer) points wire.

Now to your question:

TESTING A COIL INDEPENDANT FROM THE MAG.

NOTE: Using a low voltage ohm meter can enable you to perform some preliminary checks which will show if a coil is DEFINITELY BAD, but it will NOT show if theres a high voltage insulation breakdown which will not be observeable using an ohmmeter. i.e. you may be able to tell if its BAD (not continuous/open) but just cuz it tests good using an ohmmeter, dont mean its positively a good coil. Under heat and high voltage an insulation failure can happen which a low voltage ohmmeter test will NOT find.

SIMPLE CONTINUITY AND RESISTANCE TESTS FOR PRIMARY AND SECONDARY WINDINGS

1) If you place an ohmmeter (x 1 scale) between the ground lead and the to points lead, thats the coils low voltage primary winding, which MUST BE CONTINUOUS (NOT an open) and very low ohms (under 3, Sorry I have no exact data/specs here).

2) If you place the meter between the coils side output button/terminal and ground (x 100 or x 1000 scale), thats the coils high voltage secondary winding, and it also MUST BE CONTINUOUS (NOT open), but of high ohms, maybe in the thousand(s).

3) For the coil to NOT BE DEFINITELY BAD, the primary and secondary MUST BOTH be continuous, the primary very low ohms and the secondary very high.

SIMPLE AS THAT

Notwithstandig it could still be a bad coil at high voltage per the above.

TESTIGN THE COIL INSTALLED IN THE MAG BUT INDEPENDANT OF ANY CAP OR ROTOR PROBLEMS.

If the coils installed but the cap removed and you place a wire or paper clip etc to the mags metal (ground) frame and the other end to within 1/8 inch away from the coils side output button/terminal, each time you rotate the mags rear coupler and make her snap, a good visible blue spark should jump that gap. If so, the coil n points n condensor is good. If she sparks there but NOT via out any installed cap terminals, theres a cap or rotor or terminal problem.

NOTE: On that Wico C, make sure the springy terminal on the inner cap makes good contact with the coils output button/terminal. if not, she wont transmit the spark to the outer cap n rotor.

Post back or e mail jmn50@msn.com any questions. Im pretty sure my friend Duane Larson has data n specs which may tell you more exact ohms readigns, but the general range I gave you will serve well enough to do the preliminary tests.

Good Luck n God Bless

John T

Magneeders 417-358-7863 www.magneeders.com

McDonald Carb & Ignition Jefferson, GA 706-367-4179 www.mcdcarbign.bigstep.com

Roberts Carburetor Repair Spencer, Ia 712-262-5311 www.robertscarbrepair.com

I think I bought my last one (the one I described to you that just had 2 leads out that will work for your mag, one ground lead to attach to the mags frame/case ground, and the other to the points) from Robert Beaver.

John T