4 Symptoms to Detect a Bad Trigger on Your Mercury Outboard

Marine enthusiasts understand how important a reliable outboard engine is for a pleasant boating trip. However, a broken trigger can put an end to the fun. A bad trigger can ruin a boating trip by causing misfires, backfires, and a drop in performance.

Whether you’re a seasoned boater or a novice, it’s critical to understand the warning signs of a bad trigger so you can address it right away and resume enjoying the open waters. 

In this blog, we will delve into the symptoms of a bad trigger in a Mercury outboard engine and how you can detect it before it becomes a bigger problem. Learn how to recognize the symptoms of a bad trigger on a Mercury outboard by reading on.

How Do I Know If My Mercury Outboard Trigger Is Bad?

Your outboard trigger signals when to “fire” the switch box. Although many other factors can be responsible for an unsuccessful engine start, a bad outboard trigger is to blame in most cases.

Here are some signs you should look for to determine if there is any problem with your Mercury outboard trigger:

Symptom 1: No Spark

The lack of a spark to ignite the fuel mixture, which results in the engine not starting, is a common sign of a bad trigger. 

This can prevent one or multiple cylinders from receiving enough voltage or sparks, causing a rough start or run and misfiring. 

This can be a sign that the ignition trigger is not sending the signal to maintain steady voltage output.

Symptom 2: Hard to Start

When your boat has been idle for some time, and you try to start it again, you may find it hard to make the engine run.

This is caused because of low power or a weak spark. Also, seeing the engine take longer than usual to get started is a symptom of a bad trigger in your Mercury outboard boat engine. 

Furthermore, you may experience a higher frequency of the engine getting stalled.

Symptom 3: Engine is Low on Power

A faulty trigger can cause misfires in the engine, causing it to lose power and perform poorly. Misfires can result in a “miss” or stuttering sensation in the engine’s operation, lowering its overall performance.

Symptom 4: Frequent Engine Stalling

A faulty trigger can also cause irregular ignition timing, causing the engine to stall frequently. This is risky, especially if the engine stalls while boating in rough waters.

A stalling engine can also cause difficulty restarting the engine and additional wear and tear on the starter and battery.

2 Possible Causes of a Trigger Failure on a Mercury Outboard?

Triggers can fail for one or more of the following reasons. It is important to diagnose the problem accurately before making repairs. 

Accurately diagnosing the issue will help you resolve it quickly and get back to enjoying your time on the water.

Cause 01: Age!

Mercury Outboard triggers may eventually fail due to internal malfunctions caused by corrosion and/or temperature variations. As a result, the trigger may malfunction and cause a failure.

Cause 02: Old Wire Insulation

Old or damaged wire insulation is another factor that could contribute to trigger failure on a Mercury outboard engine. 

This may result in a short circuit in the wires, which could stop the trigger from working.

 This is why it’s crucial to regularly check the wiring and insulation and replace them as necessary.

Important Consideration:

Before assuming the trigger is faulty, it is best to check the stator first, as it can cause similar symptoms. 

You can quickly test the trigger with an ohmmeter and rule it out as a potential problem. This will save time and prevent any unnecessary inspections or repairs. 

Replacement and Repair Costs of Mercury Outboard Bad Trigger

Mercury outboard triggers are simple to repair and replace. You can easily repair a faulty trigger; however, we do not recommend repairing something too old and corroded.

A new Mercury outboard trigger will likely cost between $150 and $200. However, prices may vary depending on where you live and the model and style you choose.

In addition, the labor cost will be at most $100. However, if the repair or replacement job is too complicated, it may cost you a little more. So, you can expect the whole job to be completed for under $250.

Tips for Maintaining the Mercury Outboard Trigger to Prevent Future Failures

A broken trigger or timer base can impact the power pack and overall efficiency of the outboard motor. 

Therefore, nobody should take a chance. You can use the following advice to stop your Mercury outboard trigger from failing in the future: 

  • Examine for corrosion and other damage.
  • Avoid frequent repairs by replacing them instead.
  • Regularly perform trigger bench tests to understand the current state

If you don’t know how to perform a trigger bench test, you can watch this quick video from “MerCson L6” on youtube!

Frequently Asked Questions

Now that you know what symptoms to look for when you are trying to detect a bad mercury outboard trigger, here are answers to FAQs to clear your further doubts!

What is causing my Mercury outboard to shake?

One of the most common causes of outboard engine vibration is a broken or damaged propeller. Throttling to significantly greater RPMs may amplify the vibration, indicating that your propeller is the source of the issue.

When I accelerate, why does my outboard bog down?

Material like fishing lines, seaweed, beer can rings, and practically any other object can wrap around the propeller and its spindle. This creates friction and generates the bog, stopping your boat from turning and propelling itself through the water.

Will an outboard motor run with a bad stator?

An outboard won’t function if its stator is faulty. The stator produces the engine’s electricity to ignite the fuel and run. With only one or two cylinders, an outboard won’t start without a functioning stator.

When should I change the oil in my Mercury outboard motor?

The oil and oil filter must be changed every 100 hours or annually. This annual oil change is part of many boat owners’ preparation for outboard off-season storage.

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