How often should impeller be changed?

Your boat's engine has a cooling system, powered by a water pump, which it needs to operate. The water pump pulls water from outside the engine, sends it over the power and cylinder heads, and then ejects it outside the engine block. At the heart of your water pump is a small rubber device called an impeller. If your impeller fails, the water pump cannot pull in water, and your engine will overheat ' and potentially leave you stranded far from shore, adrift with no power.

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To help avoid a critical failure like this from ever happening to you, this article covers essential knowledge every boat owner should know about this crucial device. 

In short, as a boat owner you should be aware of:

• How many hours your engine has operated between impeller replacement?
• How many months/years have passed between your impeller replacement, and has the engine been stored or garaged for an extended period? 
• What type of water has your engine been in?
• How to visually inspect your impeller

If in doubt, it is relatively inexpensive to replace your impeller yearly as part of your scheduled boat servicing.

How does the impeller work?

The impeller is a core component of how a water pump moves water around the cooling system. Here is a great video that shows how a water pump uses an impeller to operate:

Maintaining Your Impeller

How many hours your engine has operated between impeller replacement? At a minimum, you should replace your impeller according to your manual ' for example, every 200 hours. 

Over time, the vanes become rigid and work less effectively, and you may see your engine overheating. If you extend its use beyond what is recommended, cracks at the roots of the vanes will appear and you risk the vanes breaking off inside the cooling system.

How many years between impeller replacement? Has the engine been stored or garaged for an extended period? As a recreational boat owner, 200 hours may seem like a long time, so why should you worry about it? Due to the nature of the stiff rubber used and the tight fit inside the water pump, your impeller lasts longer when used regularly. Conversely, your impeller will wear faster if left for many months without use, and the blades can deteriorate and can even become stuck and break off when the engine starts up.

If you store your boat over the cold winter months, before you get back on the water be sure to get it serviced ' don't risk it.

What type of water has your engine been in? You can expect your impeller to wear much faster in muddy, sandy and saltwater conditions, and less in freshwater. Many, if not most, of our customers here in Brisbane operate regularly in such conditions. Also, if you dry-start frequently for short periods it can melt down your impeller quickly.

How to visually inspect your impeller? If you're mechanically-minded, you can visually inspect your water pump's impeller for cracks by following the instructions in your engine's manual (or by finding a video online). Inspecting your impeller regularly, even monthly may be recommended, depending on your usage. Speak to your engine mechanic for advice specific to your boat and usage.

Replacing your impeller

Ultimately, if you are unsure when your impeller was replaced or if you garage your boat for extended periods, you should definitely have it inspected and likely replaced. Doing so will give you peace of mind and help you avoid the scary experience of breaking down on the water.

Preventive Maintenance

Preventive maintenance is the most underrated service in the marine industry. As experienced marine mechanics, we've seen it all before and have the equipment and qualifications to maintain and repair engines quickly and affordably.

By being proactive with your maintenance and servicing, you'll have fewer mechanical breakdowns and more fun on the water ' and in the end, isn't that what it's all about?

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Coorparoo Marine is a trusted and experienced boat dealership in Brisbane. Our highly trained and certified staff take extreme care and pride in their work. For all your boating needs, contact us for professional and personable service.

Most inboard and sterndrive boats utilize a raw water system to cool the engine while it runs. Cold water cycling through the system keeps the engine at a safe operating temperature. Boats use impellers to take in raw water. An impeller is a hub with flexible rubber fins. When the impeller rotates, water is sucked into the cooling system.

Despite being made of rubber, impellers tend to be durable. During operation, water keeps them lubricated and prevents damage. That being said, the potential engine damage from a failed impeller is substantial. Without the impeller, your boat's engine will overheat.

As a boat owner, it's important to pay attention to the condition of your impeller. Regular seasonal inspections and replacements can prevent major headaches and expenses down the road.

What causes boat impellers to fail?

Like any moving component, rubber impellers will wear out after years of use. There are a few factors that can speed up impeller failure.

Sandy or muddy water 

If the body of water you take your boat out on is especially muddy or sandy, the life of your impeller can be reduced. Sand particles are abrasive and can quickly wear out the rubber veins of the impeller.

Dry running your boat

Rubber impellers rely on water to keep them lubricated. If your boat runs for even a few minutes (or even seconds) without water flowing through the impeller, it will shred and need to be replaced.

Sitting to long

Rubber becomes brittle and dry rotted if it is sits for too long . If you use your boat infrequently, or if it has been sitting for a few years, the impeller may have become brittle enough to fail on initial startup.

What happens when the impeller fails?

If the impeller on your boat breaks or fails, the resulting damage can destroy your engine. Without a constant supply of cold water, the engine will quickly overheat. When an engine overheats, damage to the head gasket, cylinders, and the engine block is possible. Severe damage may require an engine replacement.

How often should a boat impeller be changed?

Even if no abnormal damage is caused to the impeller, it should still be replaced on a regular schedule. Depending on how much you use your boat, impeller replacement should be done based on either hour of operation or years.

At Matson Point S, we recommend an impeller replacement every 100 hours of operation. It can take a long time to clock 100 hours, so we also recommend that the impeller is replaced every other year for the majority of outboards and sterndrives.

The one exception to this rule would be MerCruiser systems. The design of these units extends the life of impellers. MerCruiser impellers should be replaced every three years.

Let Matson Auto and Marine replace your impeller

Impellers are an inexpensive component. Staying on top of this boat service can save you thousands of dollars down the road. Our team of boat technicians has the skills and experience needed to service your boat. If it's time for a new impeller, give Matson Auto and Marine a call today or schedule an appointment online!

Are you interested in learning more about oem pump impeller? Contact us today to secure an expert consultation!