Murray, it sounds as if the clearance between friction material (clutch lining) and drive plate has to be just right for the clutch to feel right and work properly. The parts list doesn't seem to include a washer that looks especially crushable, but there is a shim (item 20, part number GT541) in between the clutches, along with a pair of light springs. I'm not clear on why you would use shims if the whole stack of parts is spring-loaded - I'm missing something in how that central stack works. It would be nice to know what the clutch plate clearance should be, to get the same pedal movement and feel as on a new mower. You could probably find out by using a feeler gauge on a new mower - from underneath, putting the gauge between the friction material and the clutch plate on one side. Since it is a sliding stack, the other clutch would have zero clearance when you did this. Alternatively you could just adjust the nuts until the pedal feels like a new mower, then measure the clearance for future reference. I don't like the sound of using thread sealing compound to hold the adjustment stable, but it might perhaps have been the original arrangement - a Greenfield dealer would know.
