Got side tracked on another starter thread, have compiled it here.
Tonight I taped the bendix fully extended,put it in,put the old starter spline in & tried turning it by hand.Turns much easier than expected,not much load at all.But I am turning it very slow compared to a starter motor,so operated the kick by hand slowly.Everything turned without binding,real smooth?But as soon as I pushed the kick harder to normal operating speed,it jammed.On inspection the bendix was moving away from the pinion gear & locking crown to crown.Keep in mind the bendix cover is off so understandable.With the cover on slow rotation all good,fast rotation locked up.
With the cover off I held the bendix with a rag,pushing in & up to keep it tight against the pinion gear.Then hit the starter(don't try this kids),it turned over really well.Then locked again as I was concentrating on not getting my fingers dragged into the bendix. Video link below of hand/kicker rotation.
https://youtu.be/-QsvLt9rT1s
I have had the case off ,fully extended the bendix to check for any contact with the case & then measured case face to bendix gear & case face to ring gear (excluding gasket).Bendix seems close enough to fully engage & clear the case. In my case the starter worked fine for a long time before playing up.The gears on the pinion & bendix look in good condition & mesh together well. I think it is the pinion shaft & bendix shaft don't sit exactly parallel & close enough together. Possible wear at each end of the bendix shaft housing? As I have replaced the bendix cover with an AS3 cover it is most likely the shaft housing in the case. With bendix out & bendix cover off,& holding the starter button, the pinion shaft spins freely with no visible wobble, looks straight & true so am going to eliminate that shaft as the problem.
New OEM bendix due next week. Current one possibly not straight.