Thanks for the advice and support on my first outing on the list.  Pat
offered to drop me the parts in the mail; Jim gave me free advice on
setting the throttle stop after I get it back together; and Bob pointed
out that I could get by just fine by disabling the thing with baling wire. 
I'm going to try and fix it right, though; the bus has been MacGuyvered 
enough already and I figure it deserves a break.

best to all
Bill