I agree with the previous comments. Both good machines. A little outdated and crude, but they chip quite well except for the small (stringy) stuff. We have a 17" at my work, it is a beast for chipping logs, but is horrible for scrubby brush. Ours has the perkins diesel and it seems to run pretty good. We have a 13" too that we never use.......and I think it is for sale....Needs work though.....