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GS4&GS4/2 Instr and Maintenence

Here is a manual of instructions and maintenence for the Eisemann GS-4 and the GS-4/2. These are basically the same device exdept that the GS-4/2 uses a special distributor cap that will internally return the unused high tension terminals to ground. This can be done at 90 or 180 degrees depending on application. The Centaur tractors used this magneto and fired at 180 degrees with two diagonal high tension terminals. They suffered from the usual woes of icky sticky goo seeping from the wound armature insulation wanting to glue things together and some suicidal pot metal.

  A problem area for these is the sleeve that holds the cam lobes. This pot metal sleeve can swell up, crack and break. It swelling is occuring, the cam lobes will not be concentric causing asymetric firing and a rough running engine.  Sometimes one can bore the sleeve straight inside and insert with shimstock. If things really get ugly a more robust solution is to make a new cam sleeve. A standard bronze bearing bored to size and drilled to accept the cams is an excellent repair.

 Also be ware of special pitch metric threads. The armature end cap screws are 4MMx.75 AND NOT THE COMMON 4mmX.7. THE threads in the housing endcap look like common 10-32 or 5MMx.8 but are actually 5MMx.75.  This manual has some useful information to help keep yours alive and well.