The magneto unit can be one of the most challenging components in the rebuild process. The coil can be weak, the magnet ring may have lost its strength, the points may be ruined, and the condenser is likely faulty. If any of these components are not correct, the spark will not be strong enough to fire the engine properly. The twin cylinder ignition system is noted for coil failures. This chapter is intended to help the reader identify, test, and repair the various magneto parts.

There are two different types of Eisemann magnetos used on the twin cylinder engine. The type D was used on the engines made from the beginning of production in late 1937 until the production was ceased in early 1942. The DA type magneto was introduced when production resumed in August of 1945 with engine serial number 980487. The flywheel on the left is the type D and the one on the right is the type DA. These flywheels appear similar when viewed from this side. The Wico type is a third variation of magneto and will be discussed in a later section of this chapter.