Many Thanks
Looks like the cause could be either the ring gear diameter or a different flywheel. As in (sorry for starting a new thread on this known problem!):
http://www.alfabb.com/bb/forums/spid...rter-woes.html
"The ring gear on the flywheel changed with the '75 models. It went from 130 teeth to 131, or vice versa, I don't know which. At any rate the early 2L starter was a .7hp while the 75-85 models had a 1.1hp starter. They are NOT interchangable, despite what some people may tell you. I believe one has an 8 tooth pinion and the other a 9 tooth pinion. But evidently according to ARI Service Bulletin Group 05 #02, the real problem is the
diameter of the ring gear and the fact that it puts the axis about half a cm farther out."
My parts suppliers don't seem to know of this problem so "buyer beware" and it's a tricky part to access.
To be sure I get the right starter this time - does anyone know where I can get a copy of this Service Bulletin.