Yamaha Outboard Temperature Sensor Location – Importance and Functions

Temperature sensors are an essential part of outboard engines. But most of the time, users don’t even know its location of it. Apart from that, they are also indifferent to its importance and functions.

So, where is the Yamaha outboard temperature sensor location and what are the other aspects? The temperature sensors are usually on top of each cylinder head on the outboard motor.

There are threaded holes inside where the sensors are under the sparkplug wires in the powerhead. Sometimes, the coolant temperature sensors may be behind the coolant pipe on the outboard of the thermostat.

The information may seem pretty vague here in this small portion. However, you won’t have to worry about it. We’ve got you covered with a full article containing everything you need to know. Please proceed further for more information.

Why Temperature Sensor Is Important?

Yamaha Outboard Temperature Sensor Location about

Temperature sensors play an important role in outboard motors. As the outboard motors are quite expensive, they have this great sensor. Temperature sensors maintain the accurate temperature and warn about overheating or underheating.

Here the thermostat does the work of maintaining the proper temperature. Maintaining accurate temperature is necessary because it ensures proper operation of the boat and efficient performance. Any overheating can cause damage to the boat or individuals in the boat.

When the temperature goes up, the thermostat allows cool water to enter the system. It can help cool down the overheating. It’s all part of the temperature sensors. The temperature sensor keeps a record of the temperature data. Then it determines whether your system is working properly.

For example, the overall fuel consumption, and heating issues are passively controlled by this sensor. The thermostat may require replacing when it fails to maintain the temperature. This is why a temperature sensor is a very important component. And it helps in many ways.

Location of Temperature Sensor

Location of Temperature Sensor

Knowing the temperature sensor location is very important. And we’re here to let you know about that. We know that there are engine cylinders in your outboard. They’re on top of each cylinder, you can find the temperature sensor inside the holes.

Depending on the manufacturer, the heating and coolant temperature sensors can be in different places. You can find them near the thermostat on the outboard motor. For the heating temperature sensors, remove the sparkplugs on the cylinder head.

You will find the sensors inside the holes connected with the thermostats. Check the manual well if you find it difficult to locate. For the coolant temperature sensors, you may have to look in different places on your outboard motor. Usually, you can find them inside the thermostat or close to the cooling system.

If you’re unsure where the cooling system is, look beneath your cylinder pipe used for air intake. They are located behind your right cylinder. Whenever you need to do anything with the cylinder, you should turn the engine off. So, basically, this is the location of the temperature sensor on your Yamaha outboard.

Signs of Failed Temperature Sensors

You’ve got to know the temperature sensor location and what it does. But there are some signs which indicate that temperature sensors are failing. So, let’s get to know about the signs of temperature sensor failure.

1. Poor Fuel Economy

Usually, more fuel is used to cool down your engine temperature when needed. And this is monitored with the help of temperature sensors. So, when the temperature sensor unnecessarily initiates the cooling process, fuel economy worsens.

That’s why poor fuel economy is a sign of a malfunctioning temperature sensor.

2. Unusual Temperature Reading

Unusual temperature readings can be a concerning issue. For example, not seeing enough temperature reading is being shown when needed. Or when it shows too cold temperature when it should have been comparatively hotter.

These are all signs of faulty temperature sensors. So, when you see such things, you should be careful and be prepared.

3. Engine damage

Yamaha Marine Overhaul-Engine damage

If the temperature sensor has failed and the engine is allowed to overheat, it can cause damage to the engine. Overheating can cause the engine to warp or crack, which can lead to costly repairs or even the need for a new engine.

4. Exhaustion of Black Smoke

When more fuel is being used than usual, the temperature sensor fails to monitor the combustion process. As a result, you may see the exhaust releasing black smoke when trying to start the outboard.

This is a clear indication that your temperature sensor is malfunctioning. So, you should take it for repair.

5. Overheated Engine

This is one of the prime signs of failed temperature sensors. For example, the sensor will show you overheating signals although the temperature is in the nominal range.

Sometimes it may show no signals as well when the engine is actually overheating. This will surely make you feel troubled unnecessarily. So, these were some of the signs indicating that your temperature sensor is at fault.

Some General Solutions

Faulty temperature sensors can bring in a lot of problems.

Because we all know how important they are in terms of functionality. So, some general solutions can be really helpful in this regard.

  • Your temperature sensors can be at fault anytime. So, keep track of it regularly. Sometimes check the temperatures externally using a laser thermometer.
  • Another precaution can be checking your sensor every time you do service of your boat. So, let the professionals inspect your sensor and give a verdict about how it’s performing.
  • Ensure proper maintenance of your engine and other components. If the engine remains well, the temperature sensor should last long as well. So, keep your eyes on that as well.

Make sure that you follow these steps to ensure a properly functioning temperature sensor.


What can cause outboard overheating?

The primary cause is faulty water flow. Lack of water flow fails the cooling system. So, the engine can overheat. Also, problems in temperature sensors can cause this problem as well. Because that will not warn you about the rising temperature.

What does a poppet valve do in a Yamaha outboard?

Poppet valve regulates the water pressure in the cooling system of Yamaha outboard engines. It opens or stays closed sensing the water pressure at low and high RPM. Thus it plays a vital role in the cooling system.

Is it possible to clean and reuse a temperature sensor?

In most cases, temperature sensors are replaced when at fault. So, usually, they are not in a condition to clean and reuse. However, depending on the type and condition, sometimes it can be reused. But it should be cleaned well.

Does a bad temperature sensor affect the ignition of the engine?

The temperature sensor directly doesn’t affect the ignition start of the engine. However, you can experience some setbacks like a hard start or a delayed start.

What’s the cost of replacing a temperature sensor?

A temperature sensor usually costs around $150 to $190. But there are other costs as well. For example, the labor cost will be around $80 to $100, and individual costs of other parts.


Hope you were able to find Yamaha outboard temperature sensor location. We have packed in some additional information as well. So, we hope that will be of use as well.

Different sensors are an inevitable part of modern technologies. So, be careful enough to maintain them.

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