While I do believe y'all to be right, I have a hard time seeing why that "lower pulley coupling shaft" so urgently needs inspection when it only sees a minimum load (drag of the lower pulley bearing) while hitting 2200 rpms.
We recently had anohter 300C "completely apart" (600h, recently bought from foreign owner G-xxx) and the mechanic showed us that very shaft, with its funny curved sprockets, and dumped it into the waste bin together with the splined "axle" of the lower pulley, as their visible wear was way off spec, on both.
Of course I can imagine that compensating for tiny engine movements relative to the frame while transmitting 190 ponies will be hard on the shaft and the splines it connects to.
Could it be that w/o load the shaft would be rattling in the pulley from the engines uneven running, having no big flywheel and lacking load?
btw. our 300C indeed does have that overrevv ignition cut off *cough*
and the FI needs a sturdy device (smartpone will do) to whack the starter relais, to make sure it actually sends electricity to the brand new, shiny high revv starter. Hence that 300C currently requires a crew of two, for startup
