View Full Version : Speedo Problems

07-26-2004, 04:54 PM
My 1999 Sammy Duvall 190 has lost both speedos. I have pulled the tubes off the MDC and both lines are clear back to the pickups (reverse), so it must be in the MDC. I tried blowing on the valves on the MDC and nothing. I assume it take very little pressure to get something on the gauges. Note that ALL other gauges work fine. I replaced the MDC in the first season, when all the gauges were out. Seems strange that if the MDC is bad, that only the speedos are out.

Any suggestions first on can an MDC be repaired - and is it even worth it. Secondly, is there a source other than MC that I can acquire one.

Any other thoughts/suggestion would be welcomed.


07-26-2004, 10:43 PM
We were told at MC training that the MDC has a 5 year warranty. If the speedos weren't drained during winterization, that may have something to do with it, but I would open it and see if there is any obvious damage.

07-27-2004, 09:41 AM
Thanks for the thoughts. I will check on the 5 year warranty.

Well, that could be the problem. I've never seen/heard anything about draining the speedos. Other than blowing the line, what are you supposed to do? Does water actually get into the MDC? How to you get it out, as there is no screws or anything that allows easy access? That brings up my next point, as to how I look in the MDC to see if anything "looks" wrong? Does it "pop" open with a little prying?

07-29-2004, 09:13 AM
Has anyone tried to get into thier MDC to check the speedo inputs?

07-29-2004, 02:41 PM
Forgive my newness, but does water travel all the way up to the speedometer and back to the pickup in the water? Both speedometers in the '95 I am buying seemed off. Is there any kind of maintenance cleaning that can be done? Compressed air to the inlet maybe?


07-29-2004, 02:45 PM
You can buy a tool from your local MasterCraft dealer that will clean the pick-ups out. A paper clip would probably work just as good. The tool has some grooves in it to kind of bore out the pick-up. I have heard that you can also remove the tube from the back of the speedo and blow air thru using air compressor. Never actually done this, so I don't know how well this works.

07-29-2004, 04:31 PM
Water should not travel more than 12" up the hose. If it does, you have a leak in the line somewhere.
If you have used a pick to clean out the pickup, disconnect at the MDC or back of the speedo (depending on your year) and use your mouth to blow back out the tube down to the pickup. If you use a compressor, DO NOT use high pressure. You will likely pop off a fitting somewhere in the boat that Murphy put where you are least able to reach. :mad:

07-30-2004, 04:57 AM
I am new here...what is the MDC? My speedos read equally until last weekend and now one reads about 10 mph less than the other. 2001 Prostar 195

07-30-2004, 11:01 AM
There are little dental cleaning tools sold at Walmart of where ever, they look like a small pipe cleaner on a plastic handle. They work great for cleaning out the pitots. Usually come in a two pack for about $3.

You'll find them by the toothbrushes and floss.