Remove the tube as it currently is. Re-install another short one that is at a 90 to the diaphragm and pointed to the right side of the plane as viewed from the front. Doesn't need to be very long, just 90 degrees to the right, aimed at the side of the fuselage/cowl. Retune the low needle for peak rpm at about 3k rpm, give or take a little, and then a crisp transition to max rpm. Then go fly.