mercury efi throttle position sensor problems

Mercury EFI Throttle Position Sensor Problems: Solved


Facing issues with your Mercury efi throttle position sensor? You are just where you need to be. Because we have just what you need. 

By this time you’ve probably figured out there is an issue with the throttle position sensor. Nevertheless, you are unable to identify the exact issue at hand. Don’t worry you’re not alone. 

But first, let’s address the mercury efi throttle position sensor problem. What actually goes wrong? 

A faulty mercury efi TPS will result in multiple problems. Such as e reduced RPM and erratic voltage change. As well as an inability to monitor air intake. But these are solvable. The solution could be throttle cable adjustment, resetting, or replacing the TPS. And throttle cam to roller adjustment. 

The entirety of this article has elaborated on each issue and its remedies. Additionally to any potential symptoms. So stay around.

Let’s begin!

Mercury EFI Throttle Position Sensor Problems Symptoms

The Mercury efi throttle position sensor doesn’t usually go bad. But if it occurs, there will be some obvious indications.

You should look out for these symptoms. If your jet ski is showing these symptoms, it’s probably because of the faulty throttle position sensor.

Here are some of the most common symptoms of mercury efi throttle sensor problems. 

Symptom 1 of 3:  The Warning Horn Will Sound

The warning horn should emit if your TPS is malfunctioning.

You could easily panic hearing the warning horn. Be at ease, though! There’s no need to worry. As it isn’t as frightening as it seems

Symptom 2 of 3: Check Engine Light Will Illuminate

You could be worried because the check engine light is illuminating. What could that mean? 

Well, the check engine light could illuminate because of various reasons. For example, if the engine doesn’t have sufficient engine fluid the light could illuminate. 

Hence make sure to check for the TPS issues after changing the engine fluid. The mercury as well as the Mercruiser needs engine fluid change before going to the TPS

 But generally, it illuminates because of throttle position problems. 

Symptom 3 of 3: DDT will Indicate Failed TPS

You should check out the DDT. Because if you have a failed TPS then the DDT will indicate it. 

So, if you get the feeling that you’re having a failed TPS do check the DDT for assurance. 

Mercury EFI Throttle Position Sensor Problems

EFI throttle position problems are more common than you think. So if you’re facing such a problem you shouldn’t feel very unfortunate. 

Almost every other jetski owner faces this problem at some stage. It’s one of the most common jet ski problems

So, what are actually the problems that could occur because of throttle position? 

We’ve elaborated on it in your next segment. 

Problem 1 of 3: Voltage Change will be Erratic

Now could be facing erratic voltage changes. Well, erratic voltage changes could occur because of multiple reasons. 

But it mostly occurs because of faulty throttle sensor problems. 

So, if you’re facing erratic voltage you don’t need to worry. It’s happening probably because of the position throttle problem.

Problem 2 of 3: RPM will be Reduced

You’ll frequently see reduced RPM as a result of a malfunctioning TPS.

The reason behind this is the throttle sensor affects the Engine Control Module (ECM). Because of this, you’ll find RPM will not increase. It is reduced. 

Hence, if you’re facing reduced RPM it’s probably because your throttle position sensor is faulty. 

This could also result in the boat going under 2000 rpm under load

Problem 3 of 3: Can’t Monitor Air Intake

A TPS’s main responsibility is to keep track of the air intake. 

As a result, when the sensor becomes defective it fails to monitor the air intake. 

Mercury EFI Throttle Position Sensor Problem Solutions

When there is a problem there must be a solution. So don’t worry if you’re facing throttle position sensor problems. Since we have also developed solutions to the issues we’ve listed.

So, without missing a beat, let’s begin addressing your issue. 

Solution 1 of 3: Adjust the Throttle Cable 

The first thing you need to do is to check the throttle cable adjustment. The throttle stop screw should be in a particular position when the engine is started. 

You’ll find the throttle stop screw on the throttle on the arm. This screw ought to be resting on the cylinder block’s throttle stop. 

If required, preload the throttle cable barrel by one or two turns.

Solution 2 of 3: Reset or Replace the TPS

You may only need to reset a defective TPS occasionally. You could consider this as the Mercury efi throttle position sensor adjustment. 

Disconnect the battery’s negative cable in order to reset the TPS. And then leave it disconnected for 5 minutes. Or you could just remove the fuse from the engine control module. 

This should reset the Mercury efi throttle position sensor.

However, if the TPS is still not working you better replace it. 

The following are some throttle position sensors that we suggest.

Product 1 
Product 2

Do check these out. If you want to purchase a new one. 

Once you have a new TPS all you need to do is first locate the TPS. Then disconnect all the wires from it. Then unscrew the bolts to take it out. 

Then after taking it or just place the new one in the older one’s place. 

And that’s how you can replace the Mercury efi throttle position sensor. 

Solution 3 of 3: Adjust the Throttle Cam to Roller

Then comes the throttle cam to roller adjustment. It is necessary to have a perfect cam to roller adjustment. 

Hence, for this, you need to troubleshoot the cam to roller adjustment. This is going to help you in the long run.

The roller could be shifting its position on the cam. It might oscillate in the cam. It happens if the roller is not sitting on the pocket area perfectly. 

This affects the TPS link arm. It causes it to pull or push on the lever that is on the TPS. This results in a change in values. 

Thus, to avoid this, the adjustment of the throttle cam to the roller should be checked. 


When did Mercury introduce fuel injection?

Mercury introduced a fuel injection in 1996. The main purpose was to improve two-stroke outboards’ efficiency and cut down emissions. In fact, Mercury was the very first company to introduce fuel injection. After the introduction of the fuel injection, Mercury successfully reduced carbon emissions. 

When did Mercury introduce their 4-stroke outboard? 

Mercury introduced their 4-stroke outboard in 1995. The 4-stroke outboard was introduced in 2 configurations. One is the 9.9 hp and the other is the 50hp. This was a massive upgrade from its older version. The upgrade enabled lower emissions, smoother and quieter operation, and reduced emissions.

Where is the throttle position sensor located?

The throttle position sensor is located on the butterfly spindle or shaft, on an EFI system. It is located there so that it can directly monitor the position of the throttle. This enables the throttle position sensor to monitor the air intake of the engine more efficiently and accurately. 


By now you should have a clear idea of Mercury efi throttle position sensor problems.

But if the sensor problem persists then you should consult a professional. Because you risk damaging your engine if you don’t understand exactly what you’re doing.

That’ll be all from us. Catch you another time.

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