Air Drive Systems starter problem

That's a 503 we're talking about.

This is out of my experience but I suggest that you start with a set of Manuals.

That's not a very helpful response on a site like this...this forum was my last resort, when no manual can be found and not even a reference to the manufacturer on the 'net.  I did figure it out, thank you, and discovered my starter armature is toast.  Unlikely I will find a replacement for a starter with no Bendix gear, that mates with another gear, operated by a clutch assembly mounted to the crankshaft.  With my budget, I'll be going to a pull starter as the replacement.

Incidentally, did you check the Historical documents section? There is some additional 503 information in there ("REPAIR MANUAL")...

https://www.rotax-owner.com/en/support-topmenu/engine-manuals#2-stroke-historical-documents

Being realistic, you are on a Rotax forum asking about a starter that is no longer manufactured by a company that no longer exists and mounts on an engine that Rotax no longer produces.

We can get you all the legacy info about the Rotax engine but the starter info is now lost to history.

Out of curiosity,  Was this an actual air-powered starter?  Or an Electric Starter made by a Company with a confusing name?

Pictures???