JD on Facebook

Troubleshooting Teleflex Speedometer Gauges

Technical Reference Manual

Speedometer (Electric Paddle Wheel Type)

  1. The Competition Speedometer is not included in this trouble shooting guide (call Tech Service 941-907-1000 for assistance).
  2. Check all wire connections to see that they are tight and not corroded.
  3. Be sure the ring terminals supplied for the three sender wires at the gauge end are crimped to bare wire and making good contact (see Fig. 1).
  4. When speedometer is first turned on, the pointer must go to zero. If not, check connections - ground "G" and ignition "I" wires.
  5. Voltage at "I" to "G" terminals should be 12-16 VDC.
  6. If spinning the sender paddle wheel does not produce speedometer movement, the system can be checked to see what component is not working by doing one of the following:
    1. If you have a tachometer, first remove 3 sender wires from the speedometer, remove tach's gray sender wire and attach to "S" terminal of speedometer. Start engine. If the speedometer pointer gives a reading, the paddlewheel sender was probably not sending a signal to the speedo and is not working.
    2. If you have a volt/ohmmeter, connect its leads to the "G" and "S" terminals of the speedo. Turn power to speedometer "ON" and rotate paddlewheel slowly. Voltmeter should show pulsing DC: 12 volts, 0 volts, 12 volts, etc. as paddlewheel rotates. If not, the paddlewheel is probably defective.
    3. Reconnect in the original manner.
  7. Be certain the paddle wheel is snapped into the transom bracket. If it is not snapped in correctly, the speedometer will work inaccurately.
  8. If the installation is correct, but the speedometer is still not accurate, the sender may not be installed at the correct angle. The old style sender is designed for a 12 transom. Installation on transoms that deviate from that angle may require use of 1 or 2 wedges (Figure 2 above) in the sender installation. The wedges can be used either thin end up or down to achieve as close to a 12 transom position as possible. The new style sender will accommodate transom angles from 13 to 20 . Installations outside that range will also require fabrication and installation of shims to bring the angle into range.
  9. The gauge's part number can be found on its housing.

Speedometer (Pitot Tube Type)

  1. The pitot tube speedometer operates by air pressure changes in the hose and speedometer. Water is pushed through the pitot into the hose, compressing the air. Air pressure increases with boat speed, causing the gauge to indicate faster speeds. There must be air in the hose. When the boat is still and the hose is removed from the back of the speedo, no water should pour from the hose. If water is in the hose, blow it back to the pitot until air bubbles exit. Reconnect the hose to the speedometer.
  2. Check hose for kinks or sharp bends that may be cutting off air flow.
  3. Sometimes when a speedometer sits in the environment for quite a while, as over the winter, the internal metal parts form a coating (verdigris). This may make it difficult for the speedometer to op er ate. However, it should recover with repeated use.
  4. If adjustable air pressure is available, standard calibration speedometers should react to the following pressures: 5 PSI = 20 MPH; 11 PSI = 30 MPH; 19 PSI = 40 MPH; and 30 PSI = 50 MPH.
  5. A standard speedometer using the Mercury/ Mariner speed pickup in the engine foot will read approximately 10% faster than with a Teleflex pitot mounted to the transom. Speedometers with the suffix "M" after the Part Number are calibrated for use with in-foot pickups. To test as in (4) above: 5.6 PSI = 20 MPH; 12.6 PSI = 30 MPH; 22.4 PSI = 40 MPH; and 35 PSI = 50 MPH.
  6. If the hose tends to blow off the hose barb connection at higher speeds (to 80 MPH), clamp a plastic wire tie over the hose on the barb.
  7. The pitot should be transom mounted at least 6" from propeller tips.
  8. If the speedometer is not working, check that the pitot has not kicked partially or all the way up. This patented kickup feature is designed to prevent transom damage from trailering or submerged objects, and should not be disabled.
  9. The pitot is weed resistant, however, debris can accumulate in its opening. Prolonged idleness in the water may attract barnacles or algae. Be sure the pitot allows water to enter the hose.
  10. When winterizing the boat, winterize the speedometer system also. Remove the hose from the speedometer head. Blow air into the hose towards the pitot. Blow out any water that may be trapped in the hose. Leave the hose loose and the inside of the speedometer should dry out over the winter (if there is any moisture in side). Reconnect the hose before launching the boat (or the hose will siphon water into the boat).
  11. Accuracy between 5 and 35 MPH requires the use of either a Teleflex pitot type 5-35 MPH speedometer or a Teleflex electric (paddlewheel) type speedometer.

TotalBoat Blogs Live Tech Support