Yamaha Outboard Thermostats, Water Pump Repair & Cooling Components

Yamaha Marine Engine Thermostats, Water Pump Repair & Cooling Components - Resources and Information

Replacing and repairing your Yamaha outboard motor has never been easier thanks to PartsVu.com’s complete selection of Yamaha outboard thermostats, water pump repair & cooling components. Need help finding the right parts for your Yamaha outboard? Check out our Yamaha Outboard Maintenance Parts Charts to locate parts by engine model.

PartsVu.com is happy to offer a broad selection of Yamaha outboard thermostats, water pump repair & cooling components to match the exact specifications of your Yamaha outboard motor. We stock a complete range of Yamaha outboard parts and products and helpful kits to help your service your Yamaha outboard cooling system, including: 

• Water Pump Repair Kits

• Yamaha Marine Outboard Thermostats

• Yamaha Outboard Water Pump Housings

• Yamaha Marine Outboard Thermostat Gaskets

If you have questions about performing maintenance on your outboard, chances are you’ll find the answers in our blog this page. We also regularly release new helpful resources like:

• Yamaha Outboard Specs & Capacities Chart

• Yamaha Outboard Engine Schematics

• Yamaha Outboard 100-hour Service Guides

Yamaha Outboard Thermostats, Water Pump Repair & Cooling Components FAQs

What are the symptoms of a bad Yamaha outboard thermostat?

Thermostats don’t gradually stop working. When a thermostat goes bad, it stops working immediately. Depending on the position of the thermometer when failure occurs, it may get stuck in the open position, allowing coolant to continually flow into the engine and potentially causing damage. On the other hand, if the thermostat fails in the closed position, the engine could potentially overheat. Symptoms of a failed outboard thermostat include, overheating, the engine going into limited power mode, increased fuel consumption, the engine fails to warm up, the engine doesn’t perform well in cold weather, water coming out of the exhaust. 

When should I change my Yamaha outboard thermostat? 

How often your thermostat needs changing depends on the number of hours you put on your outboard, as well as the conditions in which you operate your Yamaha marine engine. Consult your owners manual to find out how often the manufacturer recommends changing your thermostat. But, keep in mind, the information found in the owner’s manual is only a general guideline. If you run your Yamaha outboard frequently in salt water or water containing a significant amount of silt, you’ll need to change the thermostat more often. In general, we recommend replacing outboard thermostats every two years.

How do I service my Yamaha outboard lower unit? 

Yamaha lower unit gear lube is drained by removing the lower drain screw first and then the upper plug vent to allow air in. On most models, both plugs are clearly visible on the lower unit, but on models with low water pickups, the forward pickup will need to be removed to access the drain plug. Use a properly sized screwdriver assisted by a wrench if necessary to loosen these screws which should be pretty tight. An impact driver and hammer may be needed depending on who serviced your engine last. The drain screw has a magnetic tip, so inspect the plug after removal to see if heavy deposits exist. Some fine shavings are normal, but chunks or a large quantity of metal is cause for further inspection. Have a drain pan and extra rags handy as gear lube will begin running down the skeg as soon as you remove the upper vent plug. Be sure to collect the fiber gaskets from both plugs after removal, as these are not reusable and should be discarded.

Allow several minutes with the engine tilted all the way down to fully drain the old gear oil. Like your engine oil, inspect the spent oil for evidence of water intrusion or other contamination or metal. If you have purchased one of PartsVu’s handy lower unit oil change kits you will already have new gaskets, oil, and a pump. Screw the pump into the lower drain hole and then connect it to the quart of Yamalube gear oil or HD gear oil depending on your model. Begin pumping oil into the lower unit until oil begins to flow from the vent plug at the top. Stop pumping and wait a few minutes for all the air bubbles to work themselves out of the gearcase. After this brief pause, pump a few more pumps until clean gear oil without bubbles is flowing from the vent plug. With a fresh fiber gasket in place, install and torque the top vent plug. Unscrew your fill hose from the lower drain plug and quickly swap in the lower drain plug with a new gasket. Torque to spec and re-install the lower water pickup screen if applicable.

How do I perform a visual inspection of my Yamaha outboard lower unit?

Visually inspect the exterior of your lower unit for any signs of damage every time before you go out. If you fish, it’s a good idea, every fifty hours or so (or when necessary whichever occurs first), to remove the propeller and check for any fishing line or other debris that may be wrapped around the propeller shaft, which can cut into prop shaft seals and potentially allow water to enter the gearcase. If found, visually inspect the prop shaft seals for damage or leakage. Then check the color of your lower unit lubricant by cracking the “drain screw” on the bottom of the bullet and the “vent screw” on the side of the lower unit. Allow a small amount to drain into a clean container. If the lubricant is milky in color, you’ve got water in the lubricant. Have the lower unit seals inspected by your Yamaha Marine dealer through a pressure test, and if necessary, have the seals replaced. Pressure testing a lower unit is best performed by an authorized Yamaha Marine dealer, because depending on findings, it may be necessary to disassemble the lower unit for further inspection.

Since you are in the neighborhood – take the opportunity to lube your prop shaft, bearings, and any other wear points – Yamalube Marine Grease is good – use it!

How do I use Yamaha outboard schematics?

Looking for even more specific and in-depth information for maintaining or repairing your Yamaha outboard motor? PartsVu offers Yamaha Outboards Engine Schematics. 

Yamaha outboard schematics are typically used by technicians or DIY enthusiasts to troubleshoot and repair issues with Yamaha outboard motors. They provide detailed diagrams and information on the electrical and mechanical components of the motor, as well as their interconnections and functions.

To use Yamaha outboard schematics effectively, it's important to have a basic understanding of electrical circuits and engine components. Start by familiarizing yourself with the key components and connections in the schematic, such as the battery, ignition switch, starter motor, and spark plugs. Then, follow the circuit paths to identify any potential issues, such as a broken wire or faulty component. You can use a multimeter to test circuits and components for continuity and resistance, and refer to the schematic for guidance on which parts to replace or repair. It's also important to follow safety procedures when working with electrical systems and to refer to the manufacturer's instructions for any specific procedures or precautions.

What is the life expectancy of my Yamaha outboard engine?

Yamaha outboard engines have a strong reputation for reliability, and for good reason. Your outboard engine life expectancy, at minimum, is about 1,500 hours (or, 6-8 years for the average boater). However, a properly maintained outboard engine can last more than 4,000 hours! This means that your engine could last for 16-21 years before needing to be replaced. 

Shop for the boat parts you need with PartsVu and reference our Marine Tool Kits guide to learn about the tools essential to your engine maintenance. If the troubleshooting guide above provided no results, consult a mechanic. They may find the issue, or you may need to replace your outboard altogether.

How do I change my Yamaha outboard lower unit’s lubrication? 

Yamaha recommends replacing your lower unit lubricant after the first 20 hours for a new outboard, then every 100 hours after that. Also, if it’s milky in color or smells or looks burnt when you’re checking it, it’s time for a change. To do it yourself, place a pan under the bottom drain screw, remove the screw, and then remove the upper vent screw on the side of the lower unit. Allow all of the lubricant to drain into the pan. While you’re waiting, check the drain screw. It’s magnetic, so any metal particles or shavings present in the lubricant will be attracted to it. Fine metallic dust is normal, but if you find larger chips of metal on the screw or in the pan as the lubricant drains, have your local Yamaha Marine dealer check for possible internal damage. Also at this time, replace the small crush washer present on each screw (commonly known as “drain plug gaskets”). If you don’t see one, it may still be adhering to the outboard. Use a pick to pull it free, as these must be located, discarded, and replaced each time these screws are removed.

Once all the lube has drained, refill the lower unit by threading the appropriate fitting into the lower unit drain screw opening (on the bottom of the bullet) and slowly pumping in fresh Yamalube Marine Gearcase Lube or Lubricant HD. Once you see this new fluid seeping out of the upper vent screw hole, stop and wait 5 minutes, then very slowly continue pumping until it seeps from the vent screw again. At this point, replace the vent screw with a new crush washer installed, and tighten it according to manufacturer specifications. Remove the fitting attached to the drain screw opening, and quickly re-install the drain screw with the new crush washer installed. Tighten to factory specifications.

You may choose to do these procedures yourself, or you can have your authorized Yamaha Marine dealer do them for you. Either way, performing them is important for proper continued operation and your continued satisfaction and enjoyment.

How do I know if my Yamaha outboard thermostat is bad?

There are a few signs that your Yamaha outboard thermostat may be bad, including a high engine temperature, poor engine performance, or water not circulating through the engine. If you suspect your thermostat is bad, it's best to have it inspected and replaced if necessary by a professional mechanic.

How often should you change a thermostat on a Yamaha outboard?

Yamaha recommends replacing the thermostat on their outboard motors every three years or every 300 hours of operation, whichever comes first. However, if the motor is used in harsh conditions such as saltwater, muddy water, or dusty environments, it may require more frequent thermostat replacements.

How do I know if my boat thermostat is bad?

Similar to a Yamaha outboard thermostat, signs of a bad boat thermostat include a high engine temperature, poor engine performance, or water not circulating through the engine. If you suspect your boat thermostat is bad, it's best to have it inspected and replaced if necessary by a professional mechanic.

How do you check a Yamaha outboard thermostat?

To check a Yamaha outboard thermostat, you will need to remove it from the engine and test it in hot water. Place the thermostat in a pot of water and heat the water to the temperature specified in your outboard motor manual. The thermostat should open at the specified temperature, allowing water to flow through it. If the thermostat doesn't open or opens too early, it may be faulty and need to be replaced.

What are the major components of a water pump?

The major components of a water pump include the impeller, housing, shaft, bearings, and seals. The impeller is the component that moves the water, while the housing holds the impeller and directs the water flow. The shaft connects the impeller to the motor, and the bearings and seals keep the water pump operating smoothly.

What are the 7 major parts of a water pump?

The 7 major parts of a water pump are the impeller, housing, shaft, bearings, seals, gasket, and mounting bolts. The gasket provides a seal between the water pump and the engine, while the mounting bolts secure the water pump to the engine block.

What parts do you need to replace a water pump?

When replacing a water pump, you will typically need to replace the impeller, housing, and gasket. It's also a good idea to replace the bearings and seals, as they can wear out over time and cause leaks or other issues.

Is the water pump connected to the cooling system?

Yes, the water pump is a critical component of the engine's cooling system. It circulates water from the lake or ocean, through the engine block and back out again, helping to regulate the engine's temperature and prevent overheating.

Is it possible for running Yamaha outboard without thermostat?

It is not recommended to run a Yamaha outboard engine without a thermostat. The thermostat is a critical component that regulates the engine's operating temperature and controls the flow of coolant through the engine's cooling system. Running the engine without a thermostat can cause a range of issues, including:

1. Engine overheating: Without a thermostat, the coolant will continuously flow through the engine's cooling system, and the engine may overheat if it's unable to dissipate the heat effectively.

2. Reduced fuel efficiency: Running the engine without a thermostat can cause it to run cooler than optimal, which can result in poor fuel efficiency and increased emissions.

3. Increased engine wear and tear: A cooler engine can also cause increased wear and tear on the engine's internal components, which can lead to engine damage and decreased engine life.

If you suspect that the thermostat in your Yamaha outboard engine is faulty, it's essential to have it inspected and replaced by a qualified technician. Replacing the thermostat is a relatively simple and inexpensive repair that can help ensure that your engine operates at its optimal temperature range and remains reliable for years to come.

Does a fuel-water separating filter help cool a Yamaha 4-stroke outboard?

No, a fuel-water separating filter does not directly help cool a Yamaha 4-stroke outboard engine.

A fuel-water separating filter is designed to separate any water or other contaminants from the fuel before it enters the engine. Water or other contaminants in the fuel can lead to engine damage, reduced performance, and other issues, so it's essential to have a fuel-water separator installed in your Yamaha outboard.

While a fuel-water separator does not directly impact engine cooling, it indirectly contributes to the engine's overall performance and reliability. By removing any water or contaminants from the fuel, the engine can operate more efficiently, which can help reduce wear and tear on the engine components and reduce the likelihood of engine damage.

Can a Yamaha outboard thermostat removal be performed by a DIY mechanic?

Removing and replacing the thermostat on a Yamaha outboard engine can be performed by a DIY mechanic with some mechanical knowledge and experience. However, it's important to note that working on an outboard engine can be complex and requires a certain level of expertise and skill in order to do correctly.

To remove the thermostat, you will need to have the necessary tools, including a socket set and a replacement thermostat. You will also need to have the Yamaha outboard engine's service manual, which provides detailed instructions for removing and replacing the thermostat.

The procedure for removing and replacing Yamaha outboard thermostat can vary depending on the specific model and year of the engine. However, in general, the procedure involves removing the engine cowling, locating the thermostat housing on the engine block, removing the bolts that hold the housing in place, and carefully removing the thermostat.

What does a Yamaha outboard thermostat rough idle mean?

If the thermostat in a Yamaha outboard engine is faulty or not functioning correctly, it can cause rough idling. The thermostat regulates the engine's operating temperature and controls the flow of coolant through the engine's cooling system. If the thermostat is stuck open, it can cause the engine to run too cool, resulting in a rough idle.

When the engine is running too cool, it may take longer to reach its optimal operating temperature, which can cause rough idling, misfires, and reduced performance. Additionally, a thermostat that is stuck open can prevent the engine from reaching its optimal temperature, which can lead to poor fuel efficiency and reduced engine life.

If you are experiencing rough idling with your Yamaha outboard engine, it's essential to have it inspected by a qualified technician. They can diagnose the cause of the rough idling and perform the necessary repairs to ensure that the engine is operating correctly. This may involve checking the thermostat, as well as other components of the engine's cooling system, such as the water pump, to ensure that they are functioning correctly.

 

What does a Yamaha outboard thermostat do?

The thermostat in a Yamaha outboard engine plays an important role in regulating the engine's operating temperature. It is responsible for monitoring the engine's coolant temperature and controlling the flow of coolant through the engine's cooling system.

The thermostat is located in a housing on the engine block and is designed to remain closed until the engine reaches its operating temperature. Once the engine reaches its optimal temperature range, typically between 130°F to 160°F (54°C to 71°C), the thermostat opens to allow the coolant to flow through the engine's cooling system.

The primary function of the thermostat is to regulate the engine's temperature, ensuring that it operates within the recommended range. An engine that runs too hot can lead to damage, while an engine that runs too cool can cause poor fuel efficiency and reduced performance.

Where is the thermostat on a Yamaha outboard?

The location of the thermostat on a Yamaha outboard engine can vary depending on the specific model and year of the engine. However, most Yamaha outboard engines have the thermostat located on the engine block near the top of the powerhead.

To locate the thermostat, you will need to remove the engine cowling and locate the engine block. Look for the cylindrical-shaped housing that contains the thermostat. The housing is typically located on the top left side of the engine block and is connected to the water intake hose.

Once you have located the thermostat housing, you will need to remove the bolts that hold the housing in place. Carefully remove the housing and the thermostat. Be sure to inspect the thermostat for any signs of wear or damage, such as corrosion or cracks. If the thermostat is damaged, it should be replaced with a new one.

After replacing the thermostat, be sure to reassemble the housing and tighten the bolts securely. Reinstall the engine cowling and start the engine to ensure that the thermostat is functioning correctly and the engine is operating at the correct temperature range.

How do I change the thermostat in a 250 Yamaha four stroke outboard?

To change the thermostat in a 250 Yamaha four stroke outboard, follow these steps:

• Remove the engine cover and locate the thermostat housing.

• Remove the bolts securing the housing and lift it off.

• Remove the old thermostat and clean the housing.

• Install the new thermostat, making sure the gasket is in place and the spring side faces into the engine.

• Reinstall the housing and bolts, and tighten them to the recommended torque specification.

• Refill the engine with coolant and run the engine to check for proper temperature regulation.

What are some common Yamaha outboard thermostat problems?

Some common Yamaha outboard thermostat problems include:

• Stuck closed or open: If the thermostat is stuck closed, the engine will overheat, and if it's stuck open, the engine won't reach operating temperature.

• Clogged: If the thermostat is clogged with debris or rust, it can fail to open or close properly.

• Corrosion: Over time, the thermostat housing can corrode, causing leaks or improper operation.

How many thermostats does a 60 hp Yamaha outboard have?

A 60 hp Yamaha outboard typically has one thermostat, which regulates the temperature of the engine coolant.

What is the process for replacing a Yamaha outboard thermostat?

The process for replacing a Yamaha outboard thermostat involves:

• Identifying the location of the thermostat housing on the engine.

• Removing the bolts securing the housing and lifting it off.

• Removing the old thermostat and cleaning the housing.

• Installing the new thermostat, making sure the gasket is in place and the spring side faces into the engine.

• Reinstalling the housing and bolts, and tightening them to the recommended torque specification.

• Refilling the engine with coolant and running the engine to check for proper temperature regulation.

Can you provide instructions for changing the thermostat on a Yamaha 150 outboard?

To change the thermostat on a Yamaha 150 outboard, follow these steps:

1. Remove the engine cover and locate the thermostat housing.

2. Remove the bolts securing the housing and lift it off.

3. Remove the old thermostat and clean the housing.

4. Install the new thermostat, making sure the gasket is in place and the spring side faces into the engine.

5. Reinstall the housing and bolts, and tighten them to the recommended torque specification.

6. Refill the engine with coolant and run the engine to check for proper temperature regulation.