I'm not sure about the gasket. I've only had the SH .18 and .28 engines. As far as the LSN, as you've probably noticed, its hard to tell where flush is. I just backed it out until it was obviously too far. I figured worst case scenario was to get it started and find it bogging down from too much LSN. That's exactly what happened. I turned it in about half a turn where it at least wanted to try and run but was still very heavy. Then I just fine tuned from there. Funny thing is, I have no problem with the needles, but I never thought my LSN being too lean would make it run hot. I guess the HSN was compensating for the LSN. You learn something evertime you play with these things.