I was given this sled about 3 weeks ago. I had been sitting for about 2 years. I cleaned out the carb, replaced the gas and oil, and put new plugs in it. It started after 3 pulls. I rode it around for maybe 10 mins. I have to have the idle set at around 2000 RPMs for it to run smoothly. If i turn the knob on the carb to drop it down, it runs really rough and it stalls. If sits for 10 seconds idling, and i try to take off, it bogs down for a couple of seconds before it starts moving. It still smokes even after it has warmed up, not to bad but i can smell oil being burnt. It also backfires under load. They aren't that bad but i can hear a pop, or a bang coming form the engine/Exhaust. I am new to snowmobiles, and i'm not sure what to do next. Any help would be greatly appreciated.

Thanks in advance,
Mike

anyone?????

Please...