Had the same problem! used it 20 minutes got very hot and tripped a breaker, tripped one after 5 seconds every other time I tried. Although mine was the 7 inch version.
I have a 4 1/2" and a 7" orange grinder and they both work fine. I have had them a couple of years each, you got a bad one.
As a side-note Home Depot has a real nice Ryobi 4 1/2" grinder with a trigger for $39.00. I picked one up a couple of days ago and I was presently surprised by it's quality. I have 4 grinders and it's the most comfortable grip of any of them.
I meant that in a "review of the nozzle" sense. I've got a half-dozenish other sprayers for all the chemicals I use on my fruit trees, pumpkins, around the house perimeter, weeds, etc...
