Ted Farmin

I have a BME 80 twin in a Hangar 9 Cap 232 , I built into the cowl pressure baffles and it seems to have a negative air press. under the engine. The engine loads up when the throttle is reduced to idle and doesn't clear out until half throttle. Has anyone expierienced this problem and if so what was your remedy? I am
thinking that I may have to cut a hole directly under the opening of the carb. and also may need to build a velosity stack that protrudes outside of the cowl. expierienced coments would be appreciated. I have already brazed a nipple on the bottom of the
diaphram plate and run a tube into the fuss. no change.