Water coming out of Speedo

[SUPRA_ALLEGRO_LANE]

Anybody have water coming out of there speedo or the tube? Have water pouring out from under the dash. And speedo is filling up inside with water.

[CJD]

The diaphram is split. Unless you can find parts for a 30 year old speedo, it's time to replace the dash instrument.

[NorCalPR]

Bad ballast tube located on the transom. It makes the water pressure, air pressure.

If that goes bad. Water pours in.


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[gnarlydude]

Just unhook it at the pick up. Quick temporary fix.


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[gnarlydude]

(In the back of the boat)


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[gnarlydude]

I forget though, is the diaphragm infuse the speedo (part of the instrument) of is it before?


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[CJD]

It's in the speedo. The tube just relays the pressure up to the speedo, where the diaphram is.

[gnarlydude]

Thanks, CJD.


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[SUPRA_ALLEGRO_LANE]

Thanks for all the advice guys, I'm gonna work on it tonight.

[NorCalPR]

It's in the speedo. The tube just relays the pressure up to the speedo, where the diaphram is.
Yep, but the speedo and the diaphragm should only see air pressure. If its seeing water there, thats before the speedo, at the ballast on the transom.

I have mine just unplugged ubder the dash when i did my perfect pass. Not a drop in the boat...

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[CJD]

Normally the tube is full of air, but the pickup is just a pinhole to allow water into the tube. As speed increases, the water fills the tube above the pickup, thereby pressurizing the air in the rest of the tube. As you slow, the pressure in the tube overcomes the water pinhole pressure, so the water is forced back out.

So, you're correct in that normally the speedo sees no water. But, if there is a hole in the speedo diaphram, then the pressurized air in the tube blends out through the hole in the diaphram...until there is no air left. Then the diaphram fills with water, and finally that pressurized water leaks out through the hole in it.