Thank you for that clarification, Aldo. I'm trying to find a way to simplify the setup of the clutch clearance, so members do not have to do it by trial and error. If we had a specific clearance to work to when setting up, the next step would be to measure the clearance when the clutch just stops working properly. Then people could check the clearance, and immediately know whether they had a clutch clearance problem or it was something else, like a belt or linkage problem. If the clutch had to be adjusted, they could compare the clearance they had with the minimum clearance, and decide on the required shim change before they even took the shaft out of the mower. Particularly with the more awkward models to work on, this might save some hassles.

Is the lip around the clutch far enough out from the clutch lining so you can flex the feeler gauge to slide it in?