Since the boat (97 Wake Challenger Merc inboard) was new, the speedometer needle has been steady up to 22mph or so, and then bounces wildly at speeds higher than that. The pitot tube appears to be clear and the inlet is right at 1.5" below the hull. I blew air into the tube at varying pressures as per manufacturers (Teleflex & Faria) standards (eg: 11PSI=30MPH)and the speedometer needle reads steady & accurate. <br /><br />My best theories at this point are 1.) The pitot tube opening needs to be deeper because it isn't getting steady water pressure at planing speeds whre it is at. 2.) The vibrations and bouncing while underway cause needle bounce due to a defective speedometer instrument.<br /><br />Anybody agree with either, or have another theory?
