Putting it all back together
I got the new stainless steel snap ring and shear pin from McMaster-Carr. The snap ring I ordered was part #91590A117 3/8" retaining ring ($6.55 for 10). The shear pin was part #98380A475 Type 416 SS Dowel pin 1/8" Dia, 1" length ($6.50 for 25).
I beleive George Irvine said (during that Techdiver George/Capt JT/Jim Cobb disscution about scooter props falling off) you can't use the clutch screw more then once (the threads won't hold if reused). So I got a new stainless steel screw from ACE 10-32x1/2 part # 4029-B ($.23).