Take a good look at the auger, impeller, and housing. See if there's any damage. 4 hours of normal use and it sounds like a good deal. 4 hours of someone blowing rocks before they decided it was "junk" and wanted a plow (or something else) and gave it a rattle can paint job may not be a good deal. I would also look at the shear bolts. The ones on my RAD blower are grade 5 and are silver in color. Check them to make sure they are the correct bolts.