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Steve B.

Speedometer Leaking

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Steve B.

This issue came up awhile ago and I never did anything about it. I removed the tube from the pitot so the speedo would quit leaking.

I do have 2 new speedo's to replace, but want to fix the root of the problem. Doing some reading, I thought it might be the balance tube, but now I"m wondering if it's just a leak in the line after the tube. One question I have is, should water be in the line at all, after the balance tube? Does air pressure keep the water from heading up the tube to the speedo?

Any thoughts ?, and thanks,

Steve B.

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BuFootin

There should not be water in the tubing past the balance tube. If you're getting water all the way up to your speedo in the dash then the tube may be bad or clogged. Best advice I'd give is get rid of those pitot tubes and go with a through hull paddle wheel or GPS speedo. Much more accurate and reliable.

good luck

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martinarcher

There should not be water in the tubing past the balance tube. If you're getting water all the way up to your speedo in the dash then the tube may be bad or clogged. Best advice I'd give is get rid of those pitot tubes and go with a through hull paddle wheel or GPS speedo. Much more accurate and reliable.

good luck

:plus1:

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vette-ski

As noted, there should not be water up in the tubes. The speedo (or MMDC black box if your boat has one) should work on air pressure. The air pressure in the tube keeps the water from coming up. So, if water is getting up, that means there's some sort of leak up under the dash that is letting water push the air out that end. Maybe you have a crack in the tube or nipple fitting or something. I had this same problem and found out the hard way. I had water get up in there but didn't leak much so I didn't know it. Over winter, it froze and cracked the black box wide open. It leaked all over first ride the next season. I added checking that box to my winterization check list just to be safe, because those boxes aren't cheap. But I think in your case, the problem is up under the dash, not on the back of the boat.

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Steve B.

As noted, there should not be water up in the tubes. The speedo (or MMDC black box if your boat has one) should work on air pressure. The air pressure in the tube keeps the water from coming up. So, if water is getting up, that means there's some sort of leak up under the dash that is letting water push the air out that end. Maybe you have a crack in the tube or nipple fitting or something. I had this same problem and found out the hard way. I had water get up in there but didn't leak much so I didn't know it. Over winter, it froze and cracked the black box wide open. It leaked all over first ride the next season. I added checking that box to my winterization check list just to be safe, because those boxes aren't cheap. But I think in your case, the problem is up under the dash, not on the back of the boat.

Thanks everyone, vette-ski, I think you are exactly right !

Steve B.

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SFD

As noted, there should not be water up in the tubes. The speedo (or MMDC black box if your boat has one) should work on air pressure. The air pressure in the tube keeps the water from coming up. So, if water is getting up, that means there's some sort of leak up under the dash that is letting water push the air out that end. Maybe you have a crack in the tube or nipple fitting or something. I had this same problem and found out the hard way. I had water get up in there but didn't leak much so I didn't know it. Over winter, it froze and cracked the black box wide open. It leaked all over first ride the next season. I added checking that box to my winterization check list just to be safe, because those boxes aren't cheap. But I think in your case, the problem is up under the dash, not on the back of the boat.

There is not a black box on a 95.

To clarify;

So your saying the air in the line from the speedo back to the balance tubes in back hold the water at the back?

If there is a leak at the speedometer or anywhere forward of the balance tubes this bleeds the air out and allows the water to come forward?

My speedo took on water last year so I am assuming the speedo has a hole within it since it filled up with water.

would the balance tubes be a culprit?

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Steve B.

I think your issue and mine are the same SFD. From what I understand, there is actually nothing in those balance tubes, other than air? I think in theory, you could hook up directly from the pick-ups and go straight to the speedo's. But the balance tubes dampen the pressure so the speedo's don't jump around wildly.

So, evidently any kind of leak past the balance tubes can allow the air to be pushed out, allowing water to go to the speedo, and maybe blow out the diaphram in the speedo.

I appreciate anybody chiming in on this,

Steve B.

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vette-ski

I guess I'm not familiar with the balance tube and what it's function is. Mine has the black MMDC box. If the balance tube is up under the dash, then I think this could be a possible source for the problem. If there's a leak it shouldn't be hard to find. Pull the hose off of the pitot on the back of the boat and have a volunteer blow into it. Listen for an air leak up under the dash. It might even be the fittings on the speedo itself. I'm not sure how yours is set up. My problem was the fittings on the MMDC box.

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jk13

As stated, there should be no water anywhere in the system. The only way for water to enter is if there is a leak somewhere to let the air out and the water take it's place.

The tubes are in the back of the boat and are there as a sort of expansion chamber to give more steady readings with less fluctuations.

Some more info here:

http://www.airguide.com.au/index.php?p=1_4

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Steve B.

Nice read, thanks JK13 !

Steve B.

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