Cleaning a Yamaha F115 Speedometer Tube

The Yamaha F115 outboard has a digital speedometer that can display speed in kph, mph or knots, also known as nautical miles per hour. You can select your preferred unit of measurement with switches on the back of the speedometer. These switches are covered with a rubber cap. To the left of this rubber cap, as you look at the back of the speedometer, is a power connector. Below the power connector is a nipple for a plastic speedometer tube. The journey to a clean speedometer tube begins there.

Things You'll Need

  • Flat-head screwdriver
  • Blow gun nozzle
  • Air compressor
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Instructions

    • 1

      Remove the four screws that hold the speedometer in place, using a flat-head screwdriver. Turn the speedometer around so you can see the speedometer tube. Hold the speedometer and insert a thumbnail on each side of the top of the speedometer tube. Push the tube off of the nipple.

    • 2

      Loosen any retaining brackets holding the speedometer tube between the speedometer's mounting location and the stern of the boat. Carry the end of the tube to the stern.

    • 3

      Attach a blow gun onto an air compressor hose.

    • 4

      Move to the outside rear of the boat. At the bottom front of the engine -- the forward edge of the lower unit -- locate the speedometer aperture. Clean any debris from the aperture. Insert the blow gun nozzle into the 3/8-inch speedometer hose aperture. Hold the end of the speedometer tube firmly. Turn on the compressed air and blow the air through the speedometer tube at less than 30 psi until the tube is unobstructed.

    • 5

      Move the tube back into the retaining brackets. Tighten the screws on the brackets snugly. Push the speedometer tube onto the nipple on the back of the speedometer. Reposition the speedometer on the dash. Thread the screws back into place with your hand and tighten snugly.