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Does Your Jet Ski Use An Alternator? [Charging System Explained]

You know, a jet ski engine is kind of like your car and truck engines in some ways, but it’s got its own quirks too.

One thing that really stands out when you compare it to cars is that instead of an alternator, a jet ski uses something called a stator. Now, you might be wondering, are a stator and an alternator the same thing?

Well, they do have some similarities, but they’re not identical. In this post, I’d like to dive into this more, and also explore the other parts of the charging system.

Jet Skis Use A Stator

Alternators are not found in jet skis and instead use a stator for their charging system.

A stator works very similar to an alternator, both charge your battery, but a stator is more focused on maintaining the charge (“trickle charge the battery“).

A stator is mostly used on smaller engines because they don’t take up as much room, “simpler”, and they can be stored inside the engine block. I consider this as a huge advantage, especially in such wet and rough environments.

A motorcycle stator and jet ski stator are similar, in fact, some manufacturers repurpose motorcycle engines.

3 Reasons For stators

There are 3 reasons why a stator is used over an alternator.

  • Stators are smaller.
  • Stators can be built into the engine, which cuts down on weight and costs of manufacturing.
  • Stators are simpler.

A stator is a simplified alternator that produces just enough power for small engines with batteries.

Saving weight, cost, and keeping it simple is the goal, and thus they use stators over alternators.

Stator Vs. Alternator

You see, the key difference between a stator and an alternator comes down to magnets.

When it comes to generating electricity, both stators and alternators play by the same rule book. They both work by moving copper wires through a magnetic field.

But here’s the twist: a stator gets its magnetic power from fixed magnets, while an alternator relies on electromagnets. That’s where they really set themselves apart.

Now, the cool thing about an alternator is that it can create its very own magnetic fields. That means its power output doesn’t depend on how fast your engine’s spinning.

RPM Dependent

A stator is dependent on the RPMs, and why it’s more of a maintainer than a charger. Due to the irregularity of power, a voltage regulator (also called a voltage rectifier) is used.

Fixed magnets allow stators to be smaller and lighter, and you can put them inside the engine block.

Charging System

Voltage Rectifier

A voltage rectifier, or also called a voltage regulator, takes the power produced by the stator and converts the AC power into DC power and smooths it out to make it more constant and predictable.

Cleans It Up

Now, here’s the deal with jet skis and their stators. You see, those magnets in the stator are set in their ways – they can’t tweak the magnetic field. So, when your engine revs up and goes faster, the stator starts cranking out more electrical power. Sounds good, right? Well, not always.

The catch is, if the stator produces too much power, it can end up zapping your sensitive electrical parts or even giving your battery a serious fry. That’s where the voltage regulator steps in to save the day.

Think of the voltage regulator as the hero that cleans up the “electrical mess.” It takes all that power and turns it into something useful. But here’s the thing, being a hero can be tough, and the voltage regulator takes a beating over time. So, don’t be surprised if it eventually wears out – it’s all part of the job.

Signs Of A Bad Voltage Regulator

One sign the voltage regulator has gone bad is that you will get a “12-Volt Low” on the display, but this could also mean the battery is bad, grounds are dirty, or a fuse is bad.

Most of the electrical issues I see tend to be a bad battery more often then a bad voltage regulator, but they do wear out.

Replacement

I consider replacing the voltage regulator as not being hard, it’s often next to the battery and comes off with a few screws and unplugging wires. (Most people could replace it with simple tools!)

Just make sure the battery is disconnected before you replace one.

How To Test Charging System

Testing the charging system to know if the stator or voltage regulator is working fine is similar to any other small engine.

With the craft out of the water, here is how you test the charging system.

  1. Connect a volt meter to the battery.
  2. Turn the engine on and look at the voltage reading.
  3. Rev the engine to 5k RPMs and look at the voltage reading.
  4. Turn the engine off, don’t run it out of the water for no more than 30 seconds.

If the voltage reading on both is NOT between 13.5 and 15 volts, then the voltage regulator or stator is bad. If the voltage reading is over 15 volts at 5k RPMs, then the voltage regulator is bad.

Here is a video on how to check the stator:

Author

Steven

I started working at a power sports dealership in 2007, I worked in parts, service counter, and as a technician before moving to sales in 2013. I created StevenInSales.com in 2014 to answer common watercraft questions I would get from people. Now managing the site full-time, I continue to provide advice and web tools for my readers about watercraft. I've owned several watercraft, with a Sea-Doo Spark as my current main PWC.

Comments

  1. This is off track from the earlier question. I have a 2003 Honda Aquatrax (sp) It’s been serviced winter and summer. Garage kept. Do have cover for it. Practically new tires on trailer. Low hours. Is it worth keeping since we don’t take it out much or should I sell it?

    Reply
    • If it’s running fine, I would keep it until it doesn’t. Honda made some great jet skis, but certain parts will be difficult to find, but you can still do the basics like an oil change and such.

      Reply

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