It won't hurt a thing to run it at the max. no-load top speed, AKA high idle. That's what they're designed to do all day.
The engine owners manual will give you the number. The equip. mfg. will tell you what the operating (load) speed will be.
Snow blowers don't have much/any parasitic load to deal with. Whereas, most ZTR and commercial walk-behinds have a lot of P.L. to take into account.
Last edited by BigFish; 01-06-2013 at 07:23 PM.