Forgot to mention the engine is inverted.. It seems to intermittently leak fuel from the carb but that seems to have tapered off a bit as I've run the engine a bit more. My other .63 is inverted too, and a bit of fuel seems to drip intermittently- but it runs fine. On the other hand, the plane (the one I'm having trouble with) will sit for an 1/2 hour plus and still have plenty of pressure in the tank when the fuel dot is removed to de-fuel.