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Why Is Boat Speedometer Not Working? – 5 Reasons to Know!

Boat Speedometer problems

A Boat Speedometer is very important to measure the water pressure and speed compared to the boat.

It helps us to know when we should increase our speed and when we should not.

But sometimes the boat speedometer can stop working. Many people don’t know the reasons and solutions for them properly.

So, why is the boat speedometer not working?

There can be many reasons behind this. Like, there can be clogs or blockages in the pitot tube or hose.

Also, leaks in the Pitot tube or hose, and problems in the fittings or wiring. Even water leaking from the dashboard.

Sometimes the problem can be in the speedometer itself as it can be faulty too.

That’s just a summary of the article. To know more about them, go through the article. Let’s start!

5 Causes of Boat Speedometer Not Working

Boat Speedometer Not Working

Boat Speedometer is a very important part of the boat. But sometimes it stops working. There can be some reasons behind this problem.

Sometimes you can also face the problem of the Boat Speedometer and boat tachometer not working altogether.

In this article, we will talk about the reasons for the Boat Speedometer not working properly and their solutions too. Go through them to know all of them.

Let’s start knowing them!

1. Blockage or clogs in the Pitot tube

A speedometer contains a tube called a pitot tube. Sometimes when water goes through this tube, the dirt, and debris of water jam the tube. That’s why it can also be a reason for the boat speedometer not working.

The water of the river can be dirty sometimes. After a lot of use, debris starts blocking the pitot tube.

When it gets completely blocked, the speedometer can’t measure the speed and pressure anymore. That’s why a boat speedometer will not work.

Do you know where the pitot tube is? The position of the Boat Speedometer pitot is below the boat and it goes through the hull of the boat.

You can easily check if there is any blockage in the Pitot tube or not through a blowgun. If there is any blockage, you will not feel the blown air of the gun.


To solve this problem you will need a drill bit. By using a drill bit, you can easily get that dirt out from the lower unit tube.

At first, you will need to find that hole, through which water enters and helps the speedometer to have the reading. The hole is in tiny size and it is probably on the leading edge of that lower unit tube.

Now, many drill bits have different sizes. The size of the drill bit depends on the diameter of the tube which has got clogged. Measure the size of the tube and buy a drill bit according to that size

Now, enter the drill bit through the hole. Power it on and move it back and forth for some time.

As a result, after some time, you will notice that it has removed all the debris and dirt from the tube. That’s the solution to the boat speedometer not working outboard.

2. A clogged or Blocked Hose

Boat Speedometer hose is also another important part of the boat speedometer. It’s made of rubber. If there is any blockage in the Hose, then the speedometer will not work properly too.

The water goes through the hose to the machine of the speedometer from the pitot tube. As I have mentioned earlier, there can be a lot of dirt and debris, and mud in the water.

It can clog the hose too as the water goes through it. If it gets clogged, then the speedometer can’t measure speed and pressure appropriately.

You can test easily if it gets clogged or not through a blowgun like before.


A clogged or Blocked Hose

You can also solve this issue through a drill bit. But sometimes the dirt gets clogged too much and it becomes hard. In that case, it will be difficult to remove the debris.

Don’t worry. I’ll tell you one more way to clean them. You can also use this to clean the pitot tube. For this, you will need

  • Syringe
  • Detergent
  • Warm Water

Fill the syringe with warm water mixed with detergent. Now through the syringe, pump that into the Pitot tube.

The detergent and warm water will remove that hard dirt by weakening them. You will have to do this several times.

After removing that dirt, pump clean water in the Pitot tube through the syringe to clean those detergents.

That’s how you can clean a hose or Pitot tube.

3. Hole in the Hose or Pitot Tube

There can be many reasons behind this problem like the boat ignition switch problem has many reasons too.

One possible reason why the boat speedometer is not working is that there might be some holes in the Pitot tube or hose.

As you know, Pitot tubes and hoses are an important part of Boat Speedometer tubing.

If there is any hole in them, then the water can’t reach the speedometer machine to measure the speed and pressure.

As a result, the boat speedometer will not show any results. That’s why if there is any hole in them, the boat speedometer will not work.

If you have checked properly that there are not any clogs in them, then there might be some holes in them. You should check for both of them.


Hole in the Hose or Pitot Tube

If there are any holes in them, then the only solution for this is to replace the tube with a new one. You need to buy a Hose of the same length and same size as before. The Pitot tube should also be the same size as before.

Go to the market and buy the appropriate one and replace it.

4. Wrong Wiring or Fitting

Still haven’t found the solution? Then the problem can be in the wiring or fitting. If there is any kind of problem in the wiring or fitting, then the boat speedometer will not work too.

To check if there is any problem or not with the wiring, you should know the Boat Speedometer wiring diagram. You should remember that a boat speedometer is different from a car speedometer.

But if you find it difficult to understand, then you can take help from an expert. You should also check the ground wire of the gauge.

There can also be some problems with the fittings too. Check all these things by an expert.


Wrong Wiring or Fitting

You can also solve the wiring and fitting issue by yourself. But for safety, you should call a mechanic to solve this problem.

5. Water leaking from the Dashboard

Another reason for which your boat speedometer is not working is that there might be some leak in the dashboard.

The water enters the machine through the hose. After that, if there is any leak in the dashboard, then the water will leak from there.

As a result, the speedometer can’t measure the speed and pressure anymore. It can also damage the interior machine part of the speedometer.


If there is any leak in the dashboard, then you should remove the dashboard and attach it with a new one. And thus you can easily solve this problem.

That’s all. Hope now you can easily determine the problem of your boat speedometer and solve it accordingly.


Boat Speedometer faqs

What is the cost to repair a boat speedometer that’s not working?

It can cost you about $100 to $250 to repair a boat speedometer. If the problem is deeper and will need additional things to repair. Then it will cost you more.

You can also find marine spark plugs for your engine.

What is speed over the ground on a boat?

Speed over the ground is the amount of speed of the vessel compared to the surface of the earth. The speed over the ground is always 5 knots.

Are there any apps for boat speedometers?

Yes, there are apps for boat speedometers. Like,  speedview, GPS speedometer, odometer, Ulysse speedometer, digihud speedometer, etc.

Can a fuse cause a speedometer not to work?

A fuse can cause a speedometer not to work. However, it’s important to understand the role that fuses play in the electrical system of your boat before making any decisions about whether or not to replace them.

Fuses are designed to protect your electrical system from overload by breaking the circuit when too much current is flowing. This prevents damage to your wiring and other components. However, if a fuse blows too frequently, it can indicate a problem with your electrical system that should be addressed.

How can I test my speedometer?

If your speedometer isn’t working properly, there are a few things you can do to test it. First, check the fuse. If the fuse is blown, replace it with a new one and see if that fixes the problem. If not, check the speedometer cable to make sure it’s connected properly. Finally, check the speedometer itself to see if it’s working properly.

What is speed over the ground on a boat

What can throw off your speedometer?

One of the most common causes of inaccurate boat speed readings is debris in the water. This can include things like seaweed, logs, or even just a build-up of dirt and grime on your boat’s hull. When this happens, it can cause your speedometer’s propeller to spin erratically, which in turn will give you an inaccurate reading.

Another potential issue is an incorrectly calibrated speedometer. If your speedometer was not properly calibrated when it was installed, or if it has been jarred loose over time, then it may no longer be giving you accurate readings. Fortunately, this is relatively easy to fix – simply take your boat to a qualified technician who can recalibrate it for you.

Bad weather can also affect the readings. Strong winds or waves can create drag on your hull, which will cause your speedometer to underestimate your true speed.


Hope you know now all the reasons for the boat speedometer not working. Go through the reasons and follow the solutions mentioned above.

It’s time to say goodbye to you. Share your experience with us about the boat speedometer in the comment section.

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