woodman .
the spring is very easy to make . infact he can make a better one way cheeper then buying a new one .
have him go down and get a piece of piano wire .
most harware stores carry K&S
if not , if he has a hobby store close that cells RC cars and planes .
3 ft should run him around 50 cents .
just bend it slowly with a set of pliers and he will have a speing that much smoother and with a better responce then the factory