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Strange one for the crew


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Finally got out for the maiden voyage of the season on my own as a chance to de-bug and see if the boat still floats after drilling several holes in the bottom of the hull. A couple of problems came up. I've found the problem to at least one, but not the cause, and I've never heard of this happening before. The first time I took off my speed seemed a lot faster than my speedo indicated, but I didn't have my gps with me to check it. Then after a few minutes of driving my guages started acting up (not working) and the tach was jumping all over the place. I've seen this in years past and usually just turning the key off and back on resets everything. Not this time. And the hour meter reads like 83,704 or something like that. That will for sure kill resale value. Then the final kicker, I have water dripping on my feet from under the dash. I look up under there and see water dripping from the plastic case where the speedo tubes attach, but not the tubes themselves. I finish my day on the water and it's now been in my garage a couple days and the hours still say 83k. I decide to pull out the whole module up under the dash and see it is cracked where the speedo's attach. The whole little housing is like half hanging off of the main case. I give it a pull thinking maybe it can be removed and it popped off. Doesn't look like it is supposed to be able to come off. Only glue would hold it back on.

So anyway, I'm wondering if maybe that piece holds water and it froze over winter and cracked the housing. Why would it do this now and never before? Anybody else seen this? Speedo works so there's no blockage at the transom ends. Or perhaps one is blocked and the other one is giving the signal for speed. I'll look at that. At any rate it looks like I need a new module. I'm thinking there's water now in this one and that's what's goofed up the guages. Thoughts??? Any idea what one of these suckers costs? On the picture the piece is supposed to flip over and the orange seals go around the speedo sensors.

post-335-1210652278_thumb.jpg

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OK, after the long post a quick search finds info that maybe water isn't supposed to be up in there until a crack shows up first. So I guess I'm not sure how it cracked so bad if it wasn't from a freeze. It didn't leak water end of last year, but sure does now.

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Unfortunately I think that is a documented problem with the MMDC. It may not be AS common now because starting in 2003 the speedo was driven by the paddle wheel. What's interesting is that there shouldn't be water that far up the system anyway.

No idea what caused it, but you definitely need a new one. Get ready to fork over some cash too, they're not exactly cheap. :(

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I had the problem of water dripping on my feet from the speedo on my old 2000 VLX. The speedo worked fine so I never worried about it much. I can't tell you what the problem ended up being as I sold the boat before it was ever fixed. Whistling.gif

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Well, the theory from a past post was only air is in the tubes if they are sealed good at the dash end. Once you get a leak source then water will push the air out and end up there. I assumed the crack was from freeze, but then water shouldn't have been there before the crack.

Are the hours stored somewhere else on the boat and just displayed on the guage, or does the guage hold the info?

Yeah, I definitely need a new MDC-1600, so if anybody has one to get rid of let me know.

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The ECM holds the most accurate hour info, so don't worry your boat won't have to be sold with 83,000 hours on it!

A dealership will need to scan the motor to read the hours, that's all.

-Chris

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I guess what I was wondering is if I buy a new MDC module (which I will have to), can I just plug it in or will the dealer have to scan the hours and then program the MDC for the right number of hours?

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Vette-ski, I have a MDC laying around if you are interested in it you can have for shipping.

I had a 2000 Malibu and i thought the MDC was my problem, ended up being a fuse. So i have the old one that was purcased in 2006 I have since sold that boat. PM me

Mike

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I replaced three MDC's before I figured out what was happening. Every spring I'd get my boat out and the gauges were either dead or acting crazy. My Dealer furnished the first MDC under warranty, but refused the second and third. I noticed every time I pulled the old unit off it had water in just as you described. I was told also water was not supposed to be there, but it was. I figured out they were freezing over the winter and busting the computer. Thus damaging the MDC.

I have removed the MDC every year since then and never had another problem. It is just part of my normal winterizing process. Dontknow.gif

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99.....Yeah, the hours are indicated on a display on the tach.

Blade.....Very gracious offer. I sent you a pm.

Bob.....Yeah, I saw one of your posts from the past. I may add this to my list now. I doubt I will pull it out every winter, but I will probably at least pull the tubes off to check for water now that this has happened.

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Seems like I remember this problem a long time ago. There was talk about putting some kind of bulb in the speedo tubes so you could blow them out easily....... like the thing when they take your blood pressure.

I haven't had the problem though. Definitely an odd one.

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Same boat. Had the same problem. It was from frozen water that wasn't supposed to be there. We ended up needing a new tach as well. The display hours are stored on the tach itself. The actual hours are on the engine ECM.

Edited by UWSkier
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Same boat. Had the same problem. It was from frozen water that wasn't supposed to be there. We ended up needing a new tach as well. The display hours are stored on the tach itself. The actual hours are on the engine ECM.

Beat me to it, hours are on the tach.

Guess you may as well just buy perfectpass now, it has a tach and hour meter built in!

-Chris

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  • 1 month later...

I just ordered my MDC for the Sanger. What a bummer I can't believe that that little water would case it to freeze. Cry.gif

$200 later and we should be back in business.

Break

Out

Another

Thousand

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