Allis Chalmers B Magneto Grounding Wire(s)

[Rumplestiltskin]

Hi, All.

I'm working on an Allis B for a friend of a friend. His wife was dragging an arena with it when it suddenly quit -- no sputtering, just instantly dead like "throwing a switch."

At first there was no spark. In the process of tracing the wires, I moved and jiggled some of them and now there is spark, although it's so weak it almost has to be nighttime to see it.

Although the wires aren't in very good shape, I didn't see any places where the (non-original)wire from the magneto straight to the ignition switch could have shorted to ground. The switch is working properly. There is, however, a second (very old-looking) wire that goes from the magneto to the upper front of the engine, then disappears into a loom on the left side.

My question: Is there any reason I can't disconnect this second wire? It looks like all it does is provide another ignition ground, which would be unnecessary as well as prone to causing trouble by shorting to ground.

Next time I go over there I'll take a mirror and try to get a better look at where these wires connect to the magneto.

Thanks in advance.

Mark W. in MI
 

[old]

Send me an e-mail and tell me which mag it has and I can send you the manual for that mag. Mags can be hard to mess with but with a manual they become easy
 

[Paul from MI]

Disconnect all ground wires from the mag to test it. If you have good spark with the ground wires disconnected, the mag is fine.
 

[chalmersbob(Pa)]

Usually the mag ground wire attaches to a screw on the visible side of the mag. The wire that goes up and around the front of the engine into a loom is thee original mag ground wire. No problem disconnecting that wire. The wires in the loom usually stay in perrty good shape but the rubber insulation can become brittle and break away causing a short. If you feel comfortable removing the cap, you can clean the points. This probably will restore your spark. LOL Bob
 

[Rumplestiltskin]

Thanks, Paul.

With all (both) ground wires disconnected, the spark is still so weak I can hardly call it a spark. I got the rotor off by prying a little harder than I really wanted to, and I can see it's been scorched/melted some but it looks like it happened a long time ago. My current plan is to clean and set the points and see if things improve. And, of course, the rotor will have to be replaced before the job's considered finished.

Mark W. in MI