by pumpguy » Sun Oct 24, 2021 1:34 pm
Taking advice from a Briggs & Stratton service manual, they caution to NOT, repeat NOT solder the spark plug wire to the tab on the HT connection of the ignition coil.
Their reasoning for this advice is soldering makes for a rigid connection, and engine vibration can cause this connection to then crack and fail. Their advice, I'm paraphrasing here, is to simply remove some insulation from the wire, run it through the little hole in the tab, then twist it around itself to make a mechanical connection, and then wrap or cover with insulating material as available.
I have seen several similar Bendix magneto coils fail due to soldered connections cracking off right where the tab comes out of the coil.
In the case of the magneto fitted to a '55 Hummer, when correctly installed, the HT lead connection is on the engine side of the coil and there is a soft cover that the spark plug wire fits through and covers this connection. its held in place by the coil and the alloy stator frame. Sorry, I don't have the P/N for this cover part.
As far as replacement coils go, a #399-125 coil for a Mercury outboard motor has the same dimensions and leads and is an effective substitute. Only difference is the LT leads come out of the coil at the opposite end so you need to either splice in extensions for these LT leads, or mount the coil with the HT tab on the side cover side, opposite the OEM Hummer arrangement.
Back in the day I had (still have) a 55 Hummer magneto grafted onto Maico engines that I used for enduro competition use. Reason for this is the lighting coil which provided reliable, if not too powerful direct lighting rather that the Maico DC generator and battery set up. Rode enduros for several years with this setup and it was totally reliable.