What To Do If Your Outboard Won’t Start

When your outboard won’t start, every minute you spend trying to find the problem is one less minute out on the water enjoying your leisure time.

Outboard won't start troubleshooting

There are ways to troubleshoot outboard problems, but here are the most common reasons why an outboard won’t start and what you can do about it. 

Gear shift not in neutral. Most outboards won’t start if the motor is in gear. Move the shifter into gear and back to neutral to make sure it's correctly set.

Outboard won't start neutral

Battery switch is off. If your boat has a battery switch, make sure it’s set to the ON position.

Kill switch disconnected. A rookie mistake just about every boater has made. Make sure the safety lanyard/kill switch is in place.

Outboard starting problems kill switch

Incorrect starting sequence. Follow your outboard’s startup sequence. For example, if your outboard needs choke before starting (manual choke knob or keyed choke during ignition), make sure you’re adequately choking the engine before trying to start it. This is especially important in cold weather, or when the motor has been in storage or inactive for an extended period of time.

Low charge or dead battery. Test the battery’s voltage. Marine batteries typically need a minimum of 12 volts to crank an outboard motor. If the battery has 10-12 volts, it can probably be charged and used again. Anything below 10 volts and it may be unable to hold a charge, which means it needs to be replaced. Also, check that the positive and negative cables are securely connected to the battery, and the terminals are clean and free of corrosion.

Blown main fuse. The motor usually has a main 20-amp fuse housed in a red fuse holder on the side of the powerhead. Check all fuses and replace them if necessary.

Outboard no start fuse

Worn starter motor. If the engine won’t crank over but you hear a clicking sound when you turn the ignition, the starter motor has failed. A short-term fix is to try tapping the starter motor a few times with a hammer. This may get the motor working a couple more times, but it’ll need to be replaced soon.

Bad/dirty spark plugs. Remove the spark plugs and clean and gap them, or better yet replace them with a new set. Check that the cables are properly attached to the spark plugs when you reinstall them.

Empty fuel tank. Another rookie mistake even the most seasoned boater makes. Whether it’s an inaccurate fuel gauge or having burned through more fuel at WOT than you realized, check the fuel tank and fill it up if necessary.

Closed fuel tank air vent. If the fuel tank can’t vent, it prevents fuel flowing properly from the tank to the outboard. Check the fuel tank vent to make sure it’s open and unobstructed.

Engine needs priming. Smaller outboards usually have a priming bulb. Give the bulb a couple of squeezes until it feels firm, which is an indication the system is now fully primed with fuel. Larger boats often use an electric primer that requires you to turn on the ignition and wait a few moments for the fuel system to prime.

Clogged fuel filters. Check the fuel/water separator filter (if your boat has one), drain out any water and replace the filter element with a new one. Also check the in-line fuel filter and replace the filter element if it appears dirty. You should change your fuel/water separator filter after every 50 hours of use and the inline fuel filter after every 100 hours regardless of their condition.

Outboard won't start fuel lines

Pinched fuel line. Check the line between the fuel tank and the outboard for kinks or pinch points that might be preventing fuel from flowing properly. Also check every fuel line connection for leaks.

Blocked exhaust outlet. The engine won’t run if it can’t vent the exhaust gasses. Check the exhaust outlet for blockages such as marine growth, fishing line or debris and remove anything you find.

Low cylinder compression. The engine also won’t run if it can’t compress the fuel/air mixture. Remove the spark plugs individually and attach a compression tester to get an idea of how well each cylinder is performing.


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