I have just started my new YS91FZ today. I am running Powermaster 20/20, an OS F plug , APC 15x8, and mounted inverted. For the first tank, 14oz, it ran well at a little richer than factory settings. I initially set the high to 1 3/4 turns and the low to 1 1/2. I ran extremely rich. After the first tank I refueled it and cranked her back over. About two minutes into the run it sounded like a hammer hitting the the piston, the engine then stopped. I removed the engine from its mount and proceeded to pour about four ounces of fuel out of the engine. There was fuel every where. After reinstalling the engine it ran well for about another two minutes and then the same thing happened, she run extremely rough. At this point I gave up and went home. When she was running she would idle around 2400 very stable and run up to 8800 at the high with fairly good transition. I have seen and know that there should be noe need for an onboard glow driver for this setup. Any ideas what is going on? Thanks.

Andrew