Regardless of the type of marine vessel you own, maintaining it and ensuring it’s in top working condition is essential. When it comes to marine vessel maintenance, one of the most important parts of the process is checking spark plugs. As a key component of your boat’s engine, marine spark plugs take in high voltage electricity at one end before igniting a spark on the other end. This spark is responsible for firing the air and fuel mixture within the engine, creating the combustion that powers the boat.

As you can likely infer, your boat’s marine spark plugs are critical to the vessel’s functionality and overall performance. So how can you tell when you have bad marine spark plugs that are causing your engine to cease functioning? Triad Diagnostic Solutions is here to share some of the most common symptoms of bad marine spark plugs so that you’ll know what to look out for.

Signs of Bad Marine Spark Plugs

When a marine spark plug begins to wear and go bad, there are a few common indicators. Luckily, these signs are fairly obvious if you know what you’re looking for or even know that you need to be aware. However, you must keep in mind that letting a spark plug go bad in any inboard or outboard engine isn’t wise. While many of these symptoms are common, they often don’t become noticeable until the problem is beyond fixing. For this reason, using your Jaltest Marine Diagnostic Full Kit is critical at any stage of maintenance.

So, here are a few signs that you have bad marine spark plugs that are putting your boat out of commission:

1. Issues starting the engine.

Much like car or truck engines, a strong spark from the plugs on your marine engine is needed in order for it to run. But, when these spark plugs start to go bad, you’ll experience a hard start or no start at all.

2. Engine hesitating or cutting out.

Sometimes, the engine will start but then cut out. This is a result of a misfire inside the motor, leading to an incomplete burn of fuel in the combustion chamber. This leads to sputtering or even a complete loss of power.

3. Decreased acceleration.

Decreased acceleration means your boat engine isn’t producing enough power. This is one of the most obvious signs of a spark plug issue. However, it could be a sign of a larger mechanical failure, something the right Jaltest diagnostic tool will be able to pick up on.

4. Loss of engine power.

Finally, a loss of power could be a result of bad spark plugs. Without the spark, an engine simply can’t run. So, if you lose complete engine power or simply can’t start up, then it’s time to check the plugs.

teenagers enjoying a day on the boat

What Should You Look for When Inspecting Marine Spark Plugs?

To know for sure whether or not you have a bad or damaged marine spark plug, you’ll need to examine the spark plugs themselves. Start by inspecting the spark plugs for damage to the insulator tip, upper and lower insulators, and boot. Next, you should check the marine spark plugs for signs of fouling.

A fouled spark plug is the result of the plug not burning fuel normally, leaving damage to the plug, which can keep the engine from starting as it should. It should be noted that while a normal marine spark plug is often dry and grayish in color, a wet spark plug could be indicative of water in the fuel. On the other hand, if the spark plug is black with soot, this usually means the fuel has too much oil. An eroded plug may mean that the plug is too hot.

When Should You Change Your Marine Spark Plugs?

If your marine spark plugs show signs of either damage or fouling, it’s probably time to replace them with new ones. This is a relatively easy fix, and you can usually get your engine running again for no more than a few dollars. The length of time in between spark plug changes depends on a variety of factors, including how often you use your boat and the way that the vessel is being used. For the best recommendations, we highly recommend consulting the owner’s manual, a trusted boat mechanic, and of course, a Jaltest Marine Vessel Diagnostic Testing tool.

Marine Vessel Diagnostic Testing Tools from Triad Diagnostic Solutions

Now that you know what to look for when it comes to a bad marine spark plug, you’ll be better equipped to notice the issue as early as possible and provide the appropriate solution. That being said, it’s much easier to be proactive about marine vessel maintenance when you have a diagnostic solutions provider on your side. Here at Triad Diagnostic Solutions, we provide cutting-edge marine vessel diagnostic testing tools that can help you catch problems with your boat before they cause damage that puts your boat out of commission.

We offer a variety of marine vessel scanning tools complete with robust diagnostic features with real-time data monitoring, automatic detection of systems and error codes, bi-directional testing, parameter reset capabilities, and integrated troubleshooting and technical information. Check out our selection today and give our free demo a try. We look forward to providing you with diagnostic tools that make all the difference!

Photo by Ferran Feixas on Unsplash