Hmm, didn't know they did work on stuff. I will have to check with them since they are just up the road from me.
As for the tiller, the last time I used it last year, once the blades were turned on and put in the ground (under load), it would start making this very loud screching noise. The blades continued to turn just fine, but I quickly shut it off after it started that. Only thing I noticed was the starter, pull cord seemed to become a little slack when it started making this noise. I am not sure if it just needs a new pull cord/spring or some kind of clutch or something is bad.