Chainsaw Repair

You can see on the side of the case of the first Stihl 066 where it had the later starter cover on it at one time. There are marks worn on the crankcase at the front.

But this chainsaw always had a poly flywheel.

I have never heard anything about the 660 starter cover not fitting the earliest 066? However some of the early 066's had different case lengths.

I cannot really answer your question as I have never owned a 066 with an aluminum flywheel.