Signs & Symptoms Of A Bad Stator On Outboard Motor? (Explained)

Outboard stators are responsible for generating electricity and passing it through the motor to operate the ignition system.

But when you have a bad stator, either the engine will become too idle or abruptly stop running.

Today’s article will help you to learn how to detect a bad stator on outboard including mercury outboard and fix it.

Bad Stator Symptoms On Outboard Motor

What Sign You Should Look For To Detect Bad Stator?

Bad Stator symptoms may vary based on the engine or motor type and sometimes become hard to figure out.

But the most easily visible and common sign of a bad stator on the outboard is when the engine fails to start because of weak or no spark and the stator is covered with salt & corrosion.

What Are The Symptoms Of a Bad Stator On Outboard?

The symptoms of the bad stator are usually similar to the below-mentioned and explained indications:

1. No Or Weak Spark:

No spark or sometimes visibly weak spark is the root sign that directly indicates that you need to check on the condition of the stator.

When the outboard engine fails or refuses to run, most likely it happens because of an old or damaged stator that fails to generate enough spark.

In some cases, the engine does not abruptly stop running or refuse to start even with a faulty spark, but one can see the almost dying performance from the outboard motor.

2. Hard Starting:

When your stator is dying, it will fail to generate enough spark and cause the engine or motor to miss or run poorly.

Therefore, if you encounter that your outboard engine is struggling to start, especially after sitting from a run, it indicates that your engine either on low power or has a miss because of a bad stator.

3. Engine Stalls And Does Not Recharge Batteries:

Because of a faulty or damaged stator, your engine may start frequently stalling.

If you experience the vessel’s batteries are in a lower voltage or going dead too quickly than usual, it is most likely happening because of that faulty stator.

Because when the stator is damaged, the engine stops recharging the vessel batteries.

Ensure whether it is happening because of the stator by checking its condition. If your existing stator shows bubbling around the battery charge windings, that means you have a bad stator problem.

How Should You React If You Detect A Bad Stator?

If you detect any of the above-mentioned symptoms, remember to use these 5 easy steps to fix the problem: –

Disconnecting Engine Batteries & Spark Plug Wires:

As soon you encounter any bad stator sign, immediately disconnect the engine’s batteries and spark plug wires. Do not start any further inspection or tests before that.

Otherwise, you can face an accident that can cause severe injury or damage if the engine cranks or starts during testing.

Diagnosis Based On Outboard Manual:

The diagnosis depends on the model of your outboard engine, so you need to perform the same procedure, which mentioned in your service manual.

Stators inspection results will vary depending on different conditions, whether hot, warm, or cold.

In some cases, you can only diagnose the failures if the engine has reached a certain operating temperature.

Therefore, before attempting to diagnose your stator’s condition, check your product’s service manual. 

Perform Required Test:

There are mainly two types of tests to inspect your stator to confirm whether it needs repair or replacement-

  1. Resistance or Ohms Test.
  2. Voltage Output Test.

Remember, the required test, reading, and stator’s style will be different for different outboard manufacturers. So, follow the spec and test instructed in your service manual.

However, for performing Ohms/resistance test, you will need an OHM meter for the Voltage Output test a DVA Meter.

Otherwise, you can even use the special Mercury DVA/MultiMeter, which works for both types of tests.

Determine The Test result & Act:

If the stator fails in Ohms or the voltage output test whichever you used based on your manual, it means the stator is damaged. Also, a bad stator eventually damages the switch box, so check on your switch box condition.

Mercury recommends, if your stator is bad enough that you need to replace it, you should replace the switch box too.

That is because an old or ruined switch box can damage your new stator shortly after installation.

However, if your test results are positive, that means your stator is not damaged yet, and check other parts’ conditions for possible issues.

Replace The Stator:

If needed, replace the stator and for that first, remove the flywheel. Since you have already disconnected all the stator connecting wires, remember every step and route.

Now remove the screws that are holding the stator in place, then also remove the old stator. To install the new stator, use Loctite and tighten the screws to 50 inches lbs. Now connect all the wires and screws accordingly in places.

Check whether the woodruff key is in place or not, and install the flywheel, battery cables again. Make sure you have followed each route correctly.

Are Replacing Bad Outboard Stator Typically Expensive?

Generally, replacing an old outboard stator with a new one is not expensive and but the replacement cost varies depending on your engine type and how difficult to reach the stator on your engine.

Additionally, if you hire a professional to do the job or take it to the servicing center, it will be a little more expensive than doing the whole thing by yourself.

However, if you are not good at such technical tasks, better letting the professional do the job.

How Often Should You Replace Bad Stator?

The general rule of thumb is to run a test whenever you see an obvious sign or symptom of a bad stator or when you have already checked other parts such as spark plug, trigger, or reed valves for possible engine troubling issues.

However, mostly a stator dies or goes bad when it is old, overcharged, or overheated, so you can keep those in mind and check your service manual instruction for accurate guidelines.

The Verdict

The Outboard Stators are the powerhouse of the ignition system because they furnish voltage to switch box or CDM’s and charge the vessel’s batteries.

However, if you see any of those mentioned symptoms on your engine performance, immediately check your engine’s stator and take proper action to fix the problem.

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