The airbox has 2 drains & each carburettor has a drip tray with a drain. All these drain points are 6mm OD and I purchased some "vacuum" hose from the local auto supply store with an ID of 5mm, it fits well and is fuel proof. I wanted to have the two hoses from each side go to a Y connector then have one hose draining overboard from there giving just two hoses at the base of the cowl. My hope was that the Y piece would provide some venturi effect as the airbox drains are subject to airbox pressure and constantly bleed some air. I connected one side that way & tried a small experiment with a few ml of water in the drip tray and a light pressure of air from my compressor simulating airbox air bleed. It was not successful as the air did travel to the drip tray & blow the water out of the tray. If that was fuel, it would be spread all over the place and certainly end up on the exhaust. I now have 4 hoses exiting at the bottom of the cowl.
