i have a super-sportster 40 with a tower-46, when im flying it it seems to run ok but when i go to a fast straightup vertical the motor almost dies,if i pump the throttle and level it off it kicks in again,if i go slow it will go vertical without doing it,i have a real good smoke trail( i think it might be a little rich) it idles good and seems to run just fine on the ground when i hold it straight up and upside down. anyone know what the problem could be? i have tried adjusting the needles but nothing helps thanks for any advice Larry

Sounds like your engine is set slightly lean. The extra g's you are pulling in a quick pull up starce the engine and you aren't rich enough for it to recover when going vertical. Hold your plane vertical on the ground for several seconds, maybe 10-15, to see if it leans out or keeps running. If it is max lean in a prolonged vertical, it probably won't stand the extra g's of a snap pull up. In this case, you'll have to run richer.

I had this problem in high G turns. I believe it's that friggin muffler. I took a 1/4 AL tube and JB Welded it to the inside of the stinger, to increase back pressure a little bit, and that solved it. If it's not lean in the vert, than try reducing the ID of the stinger.

i held it vertical for about 20 seconds wide open and it doesnt die, is the ID of the stinger the way the exhaust is pointing? mine goes up right now. would putting an os muffler on it be the same as the tubing and j-b weld? thanks guys Larry