I have noticed that this engine will run with out the exhaust line hooked up to the muffler. That tells me that it's not fuel draw problem. Maybe the OS#8 is just too cold for this engine. One of my Fox idle bar plugs decided it would start working again(it must have been flooded) and I fired it up at the shop where I work for one of the tire techs. With the Fox plug, no problem. It throttles up, transitions, and screams like a banshee. Perhaps I'm just left to running idle bar plugs all the time?