2000 200 Yamaha Saltwater with new gauges worked for a while and quit. Checked all fittings and blew low pressure air into the fittings from the motor back to the speedo and it worked. Got it all the way down to the fitting at the lower unit and from there down it is PLUGGED. Tried blowing air from top of lower unit down and nothing going. Dealer I bought the motor from said air usually does the trick. Any other remedies that would help. My service manual for the motor doesn't really give much of a breakdown. I may just add an external pitot tube like the old motor had. Seems to be a common problem with the built in tubes. I know a guy with 2004 Johnson 4 stroke with the same problem but the air trick worked for him.