How Do I Know If The Thermostat is Bad On My Evinrude Outboard?

How do I know if the thermostat on my Evinrude outboard is bad? The engine seems to be overheating and has a lack of power when trolling for a while.

There are a few ways to determine if the thermostat on your Evinrude outboard is bad. Here are some common symptoms and troubleshooting steps:

  1. Overheating: If your outboard engine is overheating, it could be a sign that the thermostat is stuck in the closed position. This prevents coolant from circulating through the engine and can cause it to overheat.
  2. Lack of power: A bad thermostat can also cause your outboard engine to lose power and not perform as efficiently as it should.
  3. Temperature gauge not working: If the temperature gauge on your outboard engine is not working properly, it could be a sign that the thermostat is faulty.

To troubleshoot, first check the thermostat for any visible damage or debris that could be blocking the coolant flow. If the thermostat looks okay, try removing it and testing it in boiling water to see if it opens and closes properly. If it doesn't, it needs to be replaced.

It's also a good idea to check the condition of the coolant and make sure it is clean and at the correct level. If the coolant is dirty or low, it can affect the thermostat's performance and cause it to malfunction.

In general, if you suspect that your outboard engine's thermostat is bad, it's best to have it checked and replaced by a trained mechanic to prevent further damage and ensure optimal performance or download an Evinrude outbaord repair manual at and fix it yourself.

What are the thermostat servicing procedures for a 2009 40 horsepower Evinrude E-TEC? How Do I remove it and install a new part?

To service the thermostat on an Evinrude 40hp outboard motor, follow these steps:

  1. Disconnect the power to the boat and remove the cowling or engine cover to access the thermostat.
  2. Locate the thermostat and its housing, which is typically found near the water pump or exhaust manifold.
  3. Using a socket wrench, remove the bolts or screws that hold the thermostat in place. Carefully remove the thermostat and its housing.
  4. Inspect the thermostat and its housing for signs of damage or debris. Clean the housing and thermostat with a soft cloth and warm water.
  5. Replace the thermostat if it is damaged or not functioning properly. Here's a good place to buy a new thermostat cheap.
  6. Install the new thermostat and its housing, securing it in place with the bolts or screws.
  7. Reconnect the power to the boat and test the thermostat to ensure it is functioning properly.
  8. Replace the cowling or engine cover and tighten all bolts or screws.

Overall, servicing a thermostat on your Evinrude outboard is essential to ensure the smooth and efficient operation of your engine. Failing to do so can lead to costly repairs and reduced performance. It can also lead to overheating and potential damage to other components in the engine. It is important to address a faulty thermostat and replace it as soon as possible to avoid further issues.

To change a bad thermostat on an Evinrude outboard motor, you will need to follow these steps:


How Do I Know If The Thermostat is Bad On My Evinrude Outboard 2009 2010 2011 40hp 60hp
Thermostat factory service procedures for 2009 Evinrude E-TEC 40, 50, 60, 65 HP

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