Disconnecting Speedometer Tube

[pigeon]

Not sure how to remove tube from back of speedometer. There are small screw beside the tube that I removed. I pulled and twisted on the tube to no avail. I don't want to break it. Can I just cut the tube off?

Thands

 

[Frank Acampora]

Replace the screws. They hold the Bourdon tube assembly inside the case. The plastic tube tends to get hard and inflexible with age. It is on a barbed fitting. Cut a slit on the side and wiggle the tube off. Remember to disconnect the tube at the pitot tube (plastic sening unit) at the transom. Failure to do this will result in a stream of water coming out the tube when underway.

 

[Alumarine]

Remember to disconnect the tube at the pitot tube (plastic sening unit) at the transom. Failure to do this will result in a stream of water coming out the tube when underway.

Been there (although my hose broke). It's very exciting when you see water pooling on top of the deck. My first thought was I was sinking.

 

[gm280]

Yes make sure you disconnect it at the pitot pickup or you will get wet for certain. If you don't think that much water would come into the boat, try it once and see... Amazing amount from just boating across the water.... Why the gauge doesn't see any water is because the water in the pitot tube forces the air in the tube to pressurize and that pressure is what the gauge sees and displays as speed. Notice how the graduations on the gauge are not uniformed. That's why. The pressure is not linear, and therefore the actual water never gets to the gauge unless there is a break in the tube or gauge.