The FC1 is a small somewhat rare Robert Bosch product made in Germany. Some versions were used by Gravely, Homelite generators, Fairmount railway speeder engines and likely more. It was well made and many survive today. They suffered the usual woes of the wound armature design and sticky goo. The condensers were sometimes a problem and hard to find in useable condition. They also mounted in a difficult place to retrofit. Bad threads can be found on these from years of abuse and neglect and from mechanics forgetting that they are made in Germany and have metric fasteners. The armature and base mounting bolts are standard metric threads. The plug wire is retained by affixing a special end with internal metric threads and poking into one side of the leadout tower and threading a screw into it from the other side. The screw that holds the leadout tower in place is a 4.5MM x.75.These are not readily available. Don't lose it! The magnet and base screws are 6MM. Here are some images to share from a recent arrival and the owner's manual followed by a detailed factory service parts list to help keep yours alive and well.
Here is a page from an early factory service manual with some special application information. Owner's manual to follow.
The condenser mounts in the front of the armature inside the collector spool unlike most Bosch products.
Condenser with armature end cap removed. Always check for electrical leakage first, if leaky, replace it. If not leaky, capacitance should be .1-.15 MFD or so.
To retrofit the condenser some creative electrical and mechanical engineering is required. The brass rod in the center has 4MMx.7 metric internal threads to accept the points retaining screw.
Beware of icky sticky goo!Here is a classic example with an Eisemann armature. If the armature shaft will not turn, this is probably what is going on inside. If so, put it in the oven and heat to about 250 degrees and the goo will usually let go. Be mindfull of this scenario with any and all good used magnetos with a wound armature.
More goo to go. Be sure and get it all out of the housing. Rewind time.
Here are some images from the owner's manual of the day to share to care for yours.
Note that it is possible to change direction of rotation by moving the cam assembly but one must also change the breaker assembly(Interrupter) as well as noted above.
Here is a factory service parts list.