Make sure it has oil and grease.
Make sure the silencer is on tight, and not leaking between blower. The blower exhaust is LOUD without a proper silencer.
A week after 9-11-01 I was cleaning the international dorm (Woods Hall) at Murray State University on the end of 300' of vacuum hose, when I heard what could be described as a LOUD air raid siren.
I ran as fast as I could back to the truck (I could then), and was horrified that the noise was coming from MY truck and echoing like crazy between two dorms.
After I shut it off I found that the silencer had unscrewed and just fell off. The first of many Nick features I discovered on those machines :-)... It was too hot to handle for a few minutes.