[WildBill]

So, i need some input. I have an old Brison 4.2 side carb engine, i just rebuilt the carb and it is running flawless, without the cowl.... if i put the cowl on it runs perfectly unless inverted, or if i pull up at low throttle to enter a hover it quits, it quits if i roll knife edge. it will pull vertical and be fine as long as it has power on. if i remove the cowl it runs just fine. i am thinking it is a pressure issue but i thought that it caused the engine to richen, but its acting lean. we even had 3 guys hold it vertical on theground like we were checkin a little nitro burner(looked pretty funny) and adjustig needles didnt fix anything.Any ideas guys?
Thanks
Bill

[pschulte]

I put the diaphram that is on the side that has the hole to sense outside air pressure backwards. The engine would run but was very sensitive to air pressure. would run on the ground but terrible once in the air. Just a thought maybe check the diaphram. I found it backwards after I got mad and replaced engine after three deadstics in a row.