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If you have a boat with an outboard motor, you naturally want it to function properly. However, without an impeller the engine will not work. So this is a very important part to have, but it is also important to maintain it properly. We explain what the impeller does in this blog.

The function of an impeller

An impeller is described as a rubber impeller. This wheel ensures that the cooling water is pumped around. Without cooling water, the engine will overheat, causing it to break. The impeller therefore has an indispensable function. It is therefore important to always check whether this part still functions properly. To prevent it from breaking, it is wise to check its condition after each sailing season and, where necessary, maintain the part.

Maintenance of an impeller

Maintaining an impeller is not necessarily difficult, but you do need to know what to look for. In principle, this paddle wheel can last a number of years, but if you sail a lot or the paddle wheel is not installed completely correctly, it may need to be replaced annually. Have you scheduled maintenance for your outboard motor? Then it is a good idea to immediately take the impeller with you. Especially if you already have the tail piece loose.

Replacing the outboard motor impeller

Replacing the impeller on the outboard motor is not difficult, as long as you know what you are doing. This is how you need to know when to replace the part and how to replace it on the outboard motor.

When to replace the impeller?

If the impeller is still completely intact, you do not need to replace it immediately. But when should it be replaced? This should be done if:

  • The cooling water temperature is (too) high;
  • The outboard motor emits less and less cooling water;
  • The outboard motor emits cooling water irregularly.

Do you recognize one of the above cases? Then you should check and replace the impeller.

Which impeller do I need?

Randomly replacing an impeller with a new one is not convenient. You have to know which one you need. A neoprene impeller is suitable for engine cooling with fresh or salt water and is resistant to oil and diesel to a limited extent. A nitrile impeller is suitable for bilge pumps and highly polluted water. And a polyurethane impeller is suitable for a ballast pump on boats with wakeboarders. In addition, you should pay attention to:

  • The brand of the pump.
  • The corresponding model number. This is usually stated in the manufacturer’s documentation.
  • The measurements.

How to replace? A step-by-step plan

Would you like to know how to replace the impeller yourself? Then follow the steps below:

  • Remove the tailpiece from the outboard motor.
  • Unscrew the cover of the pump housing. Some water may come out.
  • There is a gasket between the cover and the pump housing. Remove the gasket without damaging it. If the gasket is dry, moisten it slightly.
  • Find out the direction of rotation of the impeller. Remove these with a special puller for impellers. Make sure that no rubber residues remain in the pump housing.
  • Cover the impeller and gasket with acid-free Vaseline. This can be done with a brush or spray can.
  • Place the impeller back in the correct direction of rotation. Make sure that the blades fit snugly against the walls.
  • Carefully place the gasket back in place.
  • Carefully screw the pump housing cover back on without damaging the gasket.
  • Replace the tailpiece.
  • Check whether the motor is working properly by running it in the water.

Buy an impeller at Outboard Occasions

Do you need a new impeller? Please contact Outboard Occasions. We are an official dealer of the brands Yamaha, Suzuki, Evinrude and Tohatsu. But if you need an impeller for another brand of outboard motor, you are also very welcome. We supply all parts with the associated manufacturer’s warranty.

You can also have your impeller maintained and/or replaced by us. We employ the right professionals who know exactly how to do this. Of course you can also opt for maintenance immediately. This way you can be sure that your outboard motor is in top condition for the sailing season.

More news & tips

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Preparing your outboard motor for winter

Everything about the maintenance of your outboard motor


Frequently asked questions

Here you will find answers to common questions. Is your question not listed? Please feel free to contact us. We are happy to help you.

Contact us
  • What does an impeller do?
    An impeller is a very important part of the engine. Basically it is a rubber paddle wheel in the cooling water pump that ensures that the cooling water is pumped around.
  • How often should you replace an impeller?
    It is best to check an impeller every year. In principle, an impeller does not need to be replaced every year, but if you sail a lot or if the impeller is not installed properly, the impeller may be worn out after a year.
  • How does a boat impeller work?
    An impeller is a very important part of a boat engine. It is a rubber paddle wheel in the cooling water pump that ensures that the cooling water is pumped around. The impeller works as a kind of fan that sucks in the water and transfers it to the cooling circuit of the engine.
  • Why replace impeller?
    If an impeller is broken or worn, the cooling water can become too hot. The outboard motor can also emit less and less or more irregular cooling water. In this case, the engine is no longer cooled, causing it to overheat and therefore break down.