Doesn't work again... sorry. About this clutch adjusting how do I go about that. Also earlier they said I might need to replace a pin, On which wheel the small one or big one?
If you look at the last couple of pics in that link I posted, you can see a small slot in the shaft. and also if you look at the flywheel you can see the cruve in the centre. The woodruff keys are about 2mm thick,10mm long 10mm high. They are half moon shaped.
Did you go to the zbox site and check out the tips area for adjusting your clutch???
If you take your clutch cover off and have the motor running and then try your clutch DOES the little drive gear the one that drives your fly wheel does that one spin. I'm talking about the outside of it the teeth bit. For if it doesn't then you must have done a woodruff key in that drive gear, but if it does turn then it would be the one in the flywheel. If you have it in gear and the flywheel spins but the brass centre plate/pressure plate does not then you may just need to adjust your clutch.
Ok so it is the woodruff key on the small sprocket, that is why when you tightened the screw it worked for a while and is now spinning again. I have attached of photo of the small sprocket and where the woodruff key goes. The little metal shavings you found in the clutch case were pieces of the key.