I have a 15 year old bravo one with a tube speedo pickup. The water inlet pickup is right in the center of the lower drive unit. The outlet is a bout 4 inches away at the top of the lower unit. A 1/4 inch tube connects and runs to the speedo in the dash. The speedo and the tube are all clear. I blew air through them and the speedo works and the tube is fine. When I try to blow aide through the drive, it does not come out the top of the drive unit. When I reverse the air flow, it does not come out of the inlet. Any suggestions on how to fix it????????Thanks.