I bought a 2007 Rhino 660 years ago. It already had a ton of Mods (Air Box, FS CDI, Full exhaust and Jet Kit). It sat in my trailer for a year and would not run. I took it to local Yamaha Dealer for a tune-up and service. $1900 later I pick it up with a new carb installed and new fuel pump. They drove it out and loaded it in my trailer. I just tried to unload it and it would not run. I cleaned out the fuel tank, put new fuel as well as clean jets in carb. It now runs, but will not idle without giving it a little throttle. Cable and throttle screw are adjusted all the way. It also back fires thru both the carb and exhaust. I called the shop and they left the stock jets in the carb and thru mine out. I have no idea what to do to get it running properly. Not a carb guy. Any ideas.