The sled has 1500 miles on it, I had it out two weeks ago, put 28 miles on it no issues. Last weekend at about the 15 mile mark I lost acceleration and the motor quit. I could get it started again but could tell it was only running on one cylinder. Today I changed the plugs and dumped half a bottle of sea foam into the tank thinking maybe carb issues, it starts and will idle on still one cylinder. It pops and backfires when I open the throttle. Any ideas? Picture below is the old plug I pulled out, it was sticky. I very new to snowmobiled and have limited knowledge of two stroke carburetorated engines. Any trouble shooting ideas would be greatly appreciated. I have a trip planned next weekend and need to get this thing rolling. I have video of it running after I changed plugs, etc but do not know how to post if it would help diagnose.
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