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What do I do when my marine engine is hard starting?

Trouble Starting

If you’re one of the 10.6 million power boaters in the U.S., there’s probably nothing better than to gather up the family, and/or invite a few friends over and head to the marina for a day of boating around your favorite lake or river. A day of boating is not to be taken lightly—you have to round up all of the accoutrements, such as beverages, snacks, sunscreen for family and friends, stow everything on board and make sure the boat is fueled up. 

Nothing ends the good times quicker than hitting the starter button and listening to your engine grind and grind without the slightest indication of starting. You may not realize it, but you’ll be luckier if your engine does not start at all—at least you are still at the dock and can get some assistance. Should the engine finally start and you take off on your adventure for the day, there is always the possibility that, if you stop somewhere for a dip in the water, the engine may not start when it’s time to go home, leaving you and everyone else on board stranded. A hard starting engine is an indication of a problem waiting to happen and should be investigated right away.  

What to Look For

Any gasoline internal combustion engine needs three thing to run: air, fuel and a spark. The air and fuel must be mixed together in a specific ratio and once this mixture enters the combustion chamber, it needs a spark to ignite the mixture. With this background, the things you should look for if your engine won’t start are your air filter and the intake system, your fuel filter and the fuel supply system and your spark plugs and ignition system. 


There are many reasons why an engine may not run well, but if it won’t start at all, it’s usually related to air or fuel supply and the spark. Once you have the air and fuel filters checked and, if they are dirty, replaced and you or your mechanic is happy with the fuel and air supply, the spark plugs are the next objective. 

Spark plugs have a center electrode and a side electrode extending into the combustion chamber with a gap having a specified width between the electrodes. When high voltage from your ignition system is applied to the spark plug, a spark jumps across the gap between the electrodes to ignite the fuel/air mixture in the combustion chamber.

Keeping the width of the gap near the designed width is critical to the proper operation of your spark plugs. Residue from burning gas may form deposits that build up on the electrodes changing the gap width and weakening the spark. Or, the inner portions of the electrodes may be burned away causing he gap to become so much wider that the spark will not jump between the electrodes, resulting in spark plug failure.

What to Do

The best course of action is to make an appointment with a professional mechanic to check your engine. Removing the spark plugs and inspecting or ‘reading’ the electrodes, the mechanic can get clues as to the cause of your engines failure to start. If it’s the plugs or the filters, replacing the parts is a quick and easy repair. 

If your engine does need new spark plugs or filters, insist on reputable brand-name parts from established manufacturers, such as Champion. Champion makes different types of spark plugs and filters that are specifically tailored to your engine. Also, make sure that the parts you buy are the genuine articles, not some low-budget knock-offs. 


After your engine starts on the first turn-over, tell you family and friends that you owe them a boat trip and be prepared to take them out on the first sunny day—this time your engine will start as many times as needed and everyone will be smiling. After all, that’s what boating is all about.

Learn more about marine maintenance products, find your boat part, or find where to buy your boat part today.

The content contained in this article is for entertainment and informational purposes only and should not be used in lieu of seeking professional advice from a certified technician or mechanic. We encourage you to consult with a certified technician or mechanic if you have specific questions or concerns relating to any of the topics covered herein. Under no circumstances will we be liable for any loss or damage caused by your reliance on any content.

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