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Jet Ski Impeller 101 – What is an Impeller on a Jet Ski?
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The jet ski impeller is the key part of the propulsion system, but despite its importance, it’s often overlooked. Many owners don’t even see it until something goes wrong!
Even if you’re not a technical person, it’s wise to get to know this part. You never know when you need to remove it because of a stuck rock or debris!
Beyond the general cleaning and maintenance issues, you can also learn about servicing, replacing or even adjusting a jet ski impeller.
If you’re considering replacing your impeller, you may want to know what impeller pitch numbers mean, as well as how to choose the best impeller for your jet ski.
If you want to learn more about jet ski impellers, don’t hesitate to read more. We, at JetDrift, have gathered the most important information about this key part under one roof!
What is an Impeller on a Jet Ski?
What is an impeller on a jet ski?
In a nutshell, the impeller on a jet ski is a type of rotor with metal blades. It’s the rotating part of the pump, which is used to increase the pressure of the water. It does the same job as a propeller on a boat, as it moves the jet ski by using the engine’s power.
To put it simply, the impeller accelerates the water which finally squirts out from the backside of the jet ski with high speed. This squirting water jet moves the machine forward (or even backward) on the water.
What’s the difference between a propeller and an impeller?
Even if they do the same job, there are some differences between a propeller and an impeller. Both of these units provide thrust, but their operation is different. A propeller is a fan-like unit which converts this rotational motion into a linear thrust by acting upon the water. This thrust is generated by the pressure difference between the metal blades’ two surfaces. Unlike propellers, the impellers are located in a special pipe, known as the wear ring. Fitted tightly within this frame, the jet ski’s impeller produces a sucking force that results in a water jet. This means the pump sucks water through the intake grate, and pushes it out from the steering nozzle.
What is the impeller pitch?
What do impeller pitch numbers mean? This is probably the most frequently asked question when it comes to jet ski impellers.
Impeller pitch numbers refer to the geometry of the blades. More precisely, the numbers describe the degree of the blades, or in other words, they simply mean the amount of the pitch.The lower pitch numbers mean lower top speed and better acceleration, while impellers with higher pitch numbers can be used to reach the top speeds available.
The different pitch numbers are like the gears in your car; the impeller with a lower pitch number is the lower gear.
What are the types of impellers?
If you’re considering buying one, you can find two different types of impellers on the market. The straight pitch models feature blades that are angled the same from the front to the rear. Your other options are the progressively pitched impellers, which are unique, as they change the blades’ angle from the front of the hub to the rear.
Are you wondering what the point of this is? As we’ve mentioned, in case of a straight pitch impeller, the smaller numbers mean lower top speed and better acceleration, while the larger numbers mean the highest top speed, but you can expect decreased acceleration. So it seems we have to make compromises. But that’s where the progressively pitched impellers come into the picture. Thanks to their unique design, these models can improve the low-end power and the top speed at the same time!
How to Remove and Change a Jet Ski Impeller
Why do jet ski impellers fail?
When a jet ski impeller fails, it can fail in two ways. The first issue could be the wear and tear caused by normal use. The second, and much common impeller failure, is when the pump sucks up objects from the water which can damage the impeller and the wear ring.
These items could vary from tow ropes to debris, but the greatest damage is always caused by small rocks. That’s why every manufacturer recommends starting the engine only in water deeper than 3 feet.
How do you clean a jet ski impeller?
Once the trouble has happened and your jet ski has sucked something up, it’s imperative to know how to remove it properly.
To clean a jet ski impeller, NEVER try to reverse the jet ski or turn it over it in the water, as these actions may result in additional damage! The best practice is to turn off the engine immediately, tow the jet ski back to the dock, put it on the trailer, and then you can try to remove the sucked items.
What happens when the impeller goes bad?
If the impeller goes bad, you typically have two opportunities. First, if the damage is not significant it can be repaired by professionals. If your impeller needs repair, you can ask your dealer first or contact a special jet ski impeller repair and modification service. The company offers full service which includes blade pitch restoring, balancing as well as refinishing.
The other way is to purchase a brand new impeller. Beyond the OEM models there are countless aftermarket jet ski impellers to choose form.
Other reasons to buy a new impeller
Damage isn’t the only reason so many impellers are sold each year. If you want to make your jet ski faster, you need to modify your jet ski for better performance.
When it comes to modifications, the aftermarket high-performance jet ski impellers are really popular, so you can’t go wrong with one. Moreover, even if you modify just the engine, you probably have to replace (or at least adjust) the impeller due to the increased performance.
With the stock impellers, you can’t pull out all the extra power from the engine in many cases! For racers, replacing the impeller is one of the must-have modifications.
If you’re familiar with servicing jet skis, it makes sense to keep a spare impeller in your garage. You never know when you’ll need to replace it!
It’s always a pain if you have to replace the impeller at the end of the summer and you have to wait for the delivery. What’s more, if the two impellers have different pitch numbers, you can change them based on your needs. Finally, it’s good to know that the altitude can heavily affect the engine’s performance, so if you ride in the mountains, you probably have to replace your jet ski’s impeller.
How long does an impeller last?
If stones or other debris don’t cause damage to it, impellers can last for many years. But it’s good to know that if you ride regularly in muddy or sandy water, this results in significantly more wear on the impeller. Because of this, every manufacturer recommends inspecting the pump and the impeller every year or 100 hours, whichever comes first.
Depending on the model and the age, many jet skis feature impellers which are made of aluminum, however the current models come mainly with stainless steel impellers. Although these aluminum units do the job well in most cases, if you’re looking for something more durable, it’s recommended to replace your factory-installed aluminum impeller with a stainless-steel one.
How much does it cost to replace an impeller?
Speaking of the jet ski impeller prices, if you’re shopping around for a new one, you can expect to pay $150-$250 depending on the brand, material, and pitch. The most reputable impeller manufacturers are Solas and Skat-Trak.
Even if there’s no replacement requirement for impellers, some owners replace them regularly. They say that these replacements are still cheaper than managing the problems that can be caused by a defective impeller. (E.g. vibration, engine overheating, and many others.)
How do you choose an impeller?
The factory-installed impellers offer good performance in general, but depending on your needs, you may want to replace it for an aftermarket performance model.
Choosing an impeller is not rocket science, but it definitely needs some expertise. As a rule of thumb, you need a new impeller with a higher pitch angle if you ride in cold weather regularly, want to reach higher top speeds, or the RPM is simply too high. You may want a new impeller with lower pitch numbers if you ride in the mountains regularly (high altitude), your ski’s stock engine is low powered, or you ride regularly with a lot of extra weight.
This means if you ride with passengers and a lot of gear frequently, you may want to replace the impeller to increase the performance. Selecting an impeller for a modified jet ski could also be tricky, as many factors need to be considered.
Therefore, before you make your final choice, it’s highly recommended to check your owner’s manual for the manufacturer’s recommendations.
If you have any doubts, don’t hesitate to contact your dealer or seek advice from professionals, as selecting the wrong impeller does more harm than good.
Alternative way: adjusting the impeller pitch
If you don’t want to purchase a new one, you still have another way to change the impeller’s characteristics. “Repitching” is a kind of modification where the impeller’s blades are manually adjusted. At first glance, it looks quite odd to bend the blades in this way, but surprisingly, professionals can manage this pretty well. This is a common practice for many tuners because it’s not easy to select the perfect impeller, and this is where the repitching comes into play.
Before they buy the new impeller, they just make some water tests with the adjusted stock impeller to select the best pitch. It’s much easier and cheaper than purchasing some different impellers which ultimately do not produce the expected results.
Although it’s quite a common impeller modification, unless you have the right skills, tools, and knowledge it’s highly recommended that you don’t try it at home!
Doing it wrong can lead to several problems like cavitation or vibration due to the unbalanced impeller. In the worst case, it can damage the engine, the driveshaft or even the seals, which can result in a sunk jet ski! Instead, the best practice is if you’re looking for a service shop. In most cases, this impeller repitching service is still cheaper than purchasing a brand new impeller.
How do you remove the impeller from a jet ski?
The process of removing the impeller from a jet ski varies from model to model, but it can usually be done at home. If you have the skills and the proper tools you can do it by yourself.
How do you remove the impeller from a jet ski? As a first step, always disconnect the jet ski’s battery. If the jet ski is equipped with a brake system, you have to fold up the bracket manually, and disconnect the steering and trim linkage as well as removing a bunch of bolts. As we’ve mentioned, the process may vary depending on the model, so for further guidance, please always check your owner’s manual.
You can make also good use of these videos below, which show the process on some popular models:
How do you change the impeller on a jet ski?
Changing the impeller on a jet ski is not so difficult, however, you’ll need some tools. First, you have to remove the current impeller which comes out with the drive shaft in case of some models. To remove the old impeller from the driveshaft, or from the pump on other models, you will need some special tools. After you’ve installed the new impeller, you will also need a torque wrench to fix it in place properly.
Unless you have these special tools and experience, it’s recommended to take your ski to your dealership or a reputable service shop to change the impeller on your jet ski!
The jet ski impeller is one of the most important parts of the pump, as it provides the water jet that moves the jet ski.
It looks similar and does the same job as a propeller on a boat, but unlike propellers, the impeller’s housing is in a plastic or stainless-steel pipe, which known as the wear ring.
The quickly spinning metal blades of the impeller speed up the water, which finally squirts out from the rear side of the jet ski while moving it forward.
One of the most common issues is when a small rock or debris gets stuck in the impeller, so it’s always good to know how can you remove them properly.
If you want to replace your impeller, you can choose from plenty of aftermarket models. Always pay attention to the pitch numbers as these refer to the impeller’s geometry.
In a nutshell, the lower pitch angle means better acceleration but lower top speed, while the higher pitch angle means higher top speed but less lively attitude.
Before you replace (or adjust) your impeller always check your owner’s manual as well as consult with your dealer for further guidance!
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