I know getting spares gets more and more difficult, and some of those available gets costly.
My F2 starter motor was very poor, and with hot engine, it hardly could turn the engine.
A new motor is up to around Usd 700, so I took a look at E-bay, and found a chap in the States, who would ship me a brand new for around Usd 50. I bought, and when I received it, it turned out to be permanent magnet motor. Not bad. But really problem was that it turned the wrong way! Bad deal!
But I found a solution. Take the motor apart, dismantle the brush plate and the power bracket from the house.
Drill a new entrance for the power screw 90 degrees from the old entrance. I made the new connection clock wise to the old entrance. In the house, there was a groove for fixation of brush plate. File a new groove 90 degrees from the old one.
Now mount the brushes and end covers again, and turn the end covers ea bit over 90 degrees to the marks.
And viola! The motor rotates right now.
Hope this can be usefull for some of you guys. And it’s also saving you quite a lot of money!