3-speed starter motor

[Tony Press]

After studying the differences between a 3 speed and 4 speed brush end covers the brush end cover was turned through 90 degrees and it now runs the correct way.

Not sure what this means - I would have thought some connections would have to be reversed not just a 90 degree turn - but I am not good with electrics. 

I assume the left endplate indicates anticlockwise rotation and the right clockwise - the brushes could possibly be inverted and refitted on the opposite pins to change the rotation settings.

I will go now 

[Dave Mann]

Basically by rotating the brushes another portion of the armature is energized and the resultant armature magnetic field reacts with the fixed field magnetic field causing it to turn in the desired direction. With this motor I knew it had the correct bendix because it didn't engage the flywheel when it went the wrong way so all I had to do was reverse the direction of rotation. If you dismantle (never disassemble) a 3 speed and 4 speed starter you will also find the armatures are wound differently but in our case someone inadvertently fitted 4 brush end plate to a 3 speed motor or as an act of devilment to give another owner a problem.

[Dave Mann]

Here's a photo of the modification