speedometer not working?

[shelala1999]

I've got a 1992 monterey, it has a 3.0 mercriuser alpha one. The speedometer is not working can anyone give me any tips to fix it. This is the first boat I've ever had so I don't know much about them.

 

[5150abf]

Re: speedometer not working?

the best way to fix that is to get a GPS.

It is a pitot tube and they are horribly inaccurate and hard to keep working and even when they do work you never know if they are giving the correct speed.

There should be a plastic peice on the back of the boat that sticks just below the bottom of the boat, it has a hole in it and as the boat moves it puts pressure on a tube connected to the speedo, the faster you go the more pressure the farther it moves the needle.

You would need to find the tube on the back of the speedo and blow it out and make sure the hole at the back is clear too, then it might work but again nothing is better than GPS.

 

[TilliamWe]

Re: speedometer not working?

Actually, your speedo should be integrated in your outdrive. There is a small hole, just above the "bullet". These holes get dirt and debris in them. Take a piece of coat hanger, or a small drill bit, and Carefully clean out the hole. Also, there is a plastic fitting, shaped like a cross, that is supposed to be pushed into and turned-to-lock, in the front of the anti-ventilation plate. To see it, tilt the drive all the way up (while boat is on the trailer), and get down under the transom and look at the leading edge of the drive. Hope that helps.

 

[TilliamWe]

Re: speedometer not working?

Here's a picture of the hole, I know it's hard to see, but it's there:

And here is the tube, where it connects:

 

[smclear]

Re: speedometer not working?

the best way to fix that is to get a GPS.

+1 I have never seen a stock speedometer on a boat that was consistently accurate (unless it is within a GPS unit). If you decide to go with a GPS unit, and ONLY intend on using it for speed verification, I would recommend a Garmin Forerunner. They're designed for the sports enthusiast (jogging, biking, etc.) and don't have mapping capabilites. They are less $ than the types that come with mapping abilities. Still, if money is no object, buy the most powerful unit can get. They are fun to play with.

 

[CaptNCamille]

Re: speedometer not working?

As stated above, the intake could be clogged,

You can try taking the boat into the water, and with no boats nearby, give it a few hard thrusts in reverse. This usually clears it out.

 

[serrano4657]

Re: speedometer not working?

I bought a used boat and the speedometer did not work. I replaced the
part at the end of the tube that that sits in the water. Still did not work
after that. I finally gave up and bought a gps and never looked back.
Gps is great, mph, trip meter, compass, and so much more.

 

[FlyinGuy1017]

Re: speedometer not working?

I won't argue the GPS route on here, but I do prefer all my guages to read something. The intake for your pitot will be on the leading edge of your outdrive, about half way down from the bottom on your anticavitation plate. That is most likely where the clog is. You can verify by un-hooking the tube above the anti-cav plate and blowing compressed air into it. See if that registers on the spedo. If so, your problem is in the outdrive area.

To remove, try blowing compressed air backwards from where the tube hooks up. You can try to pry anything out from the bottom (inlet) portion, but DON'T use a drillbit. I can promise, from experience, that the only bit's small enough will break, or re-size the hole so it won't real accurately.

Hope this helps!