Making sure that your outboard is running and reliable. Makes all the difference in your experience out on the water. Having a bad stator is going to take away from that experience!
Will An Outboard Run With A Bad Stator? Yes, certain outboards will run with a bad stator, but not very well. No, other smaller outboards will not run with a bad stator. The stator produces the electricity that the engine uses to operate the ignition system to run the engine.
There are many different factors and variables to this question! Here are all of the things that you need to know to figure out which of them applies to you!
What Exactly Is A Stator?
A stator is a component on an engine that is attached under the flywheel of the engine. The engine’s flywheel has magnets attached to the inside of it, that spin around the stator.
The stator is made up of windings that produce alternating current electricity. As the magnets on the flywheel spin around the windings when the engine is running.
This AC electricity is used by the engine to run all of the ignition components of the engine. That makeup is what creates the spark for the engine to run.
For a more in-depth description of how an engine works. Read our article teaching you What Is A Powerhead & How It Works!
A stator is also the component that creates the charging power for your boat’s batteries. If the stator fails, then you won’t be charging your boat’s batteries while you are running!
We’d recommend reading this article here on How Outboards Charge The Boats Batteries By Either A Stator or An Alternator.
Signs & Symptoms Of A Bad Stator
A bad stator can have all kinds of funny, hard to trace symptoms. Making it sometimes difficult to diagnose.
It’s important to note what kind of engine you are working on. Since the stator is what creates the electricity needed for the engine to create a spark and run.
Smaller outboards that only have one, or two cylinders. It will not even start and run if the stator has failed!
Whereas larger engines, that have 4, 6, or 8 cylinders. Will use a stator that has different parts to it.
Some stators will be broken down into two, three, four, or even six halves! Meaning, that one winding will produce the electricity that is used for one, two, or three different cylinders!
So, if one winding will fail. The engine will lose spark on one or all of those cylinders. Making the engine run very poorly.
This is why you can have a bad stator, but the engine will still run, just very poorly.
Why Do Outboard Stators Go Bad?
There are many reasons for a stator to go bad. They get old, they get hot, they break down, and they just flat out go bad!
If the windings get corroded by a dirty engine, they can fry themselves. Or short out. So a dirty engine can cause a stator to go bad. As well as running too hot.
Say you wrap a bag around the lower unit and loose cooling water. Or if the thermostat gets clogged with weeds, dirt, or sand. Then the engine runs warmer than it should.
If that is left like that and you don’t address the issue. The warm temperature can melt parts of the stator. Causing it to fail!
I would say that the main cause for a stator to go bad, is due to age, heat, and corrosion. Those are the three main causes for a stator to fail.
How Do I Know If My Stator Is Bad?
You can tell the stator is bad, based on the symptoms of the engine. Though it won’t be a clear and cut situation. You will need to test the stator and we’ll cover that in a second.
You can know you have a bad stator by looking at it. If the stator is covered in salt and corrosion. Or you see it has melted or burnt windings on it. Then you could almost bet that it is bad.
Before condemning it though, you want to perform some tests to be exactly sure that the stator has failed.
How To Test An Outboard Stator
When it comes to testing the stator. You should be aware that different manufacturers are going to have different tests, different readings, and different styles of stators.
But, in the general sense, there are some tests that you can do on almost any stator and tell a lot of whether it has failed or not.
The number one test is to ground it out. In order to perform this test. You will need to have a digital multi-meter. (You can see our recommendations for a meter on our resources page here.)
What you will do, is find the plug that goes to the stator. Then disconnect it. With that disconnected. You can set the meter to read ohms or resistance.
Then connect the negative meter lead to any engine ground that is on the block. And take the positive meter lead and check for a short to ground at each and every wire that is coming out of the stator.
If you find that there is continuity between the wire going to the windings in the stator. Then you know that the stator is shorted to ground and you will need to replace the stator.
Then, on other stators, you can check the resistance between the wires coming out of the stator. Some of these stators will have a certain amount of resistance between the wires.
And others will have straight continuity between the wires. This is why it is important for you to find the service manual for the specific engine you are trying to test the stator on.
And go by the specs found in the book to test the stator. Because there is also a voltage reading that can be performed to see what kind of power the stator produces.
But you will need to have a digital voltage adapter to test this to keep the fuses in your meter from blowing. So be sure to test your engine’s stator based on the service manual specs and tests!
Will An Outboard Run Without Stator?
It depends on what style and type of engine you have. As we said earlier.
There are some larger engines that will run with a partially bad stator. While there are other smaller outboards that will definitely not run without it.
So it all depends on your engine and what kind of system it uses!
Now that you know all about outboard stators and how to test them. Here are some other articles that you will find extremely helpful and informational!
We’d also like to invite you to check us out on Our YouTube Channel! We create all kinds of how-to and DIY videos. To help you learn more and more about your boat and how it works!