My Outboard Won’t Start! What to Check First

You’re all set to hit the water with family and friends, and the cooler and the skis and/or fishing rods are loaded up. But then you turn the key and … nothing! 

So what do you do when your outboard doesn’t want to fire up? Before you dive headfirst into the toolbox, here’s what to check when you’re trying to diagnose an outboard that won’t start.

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Troubleshooting Outboard Starting Problems Checklist

Outboard No-Start Check 1: Neutral

Check to see if the motor’s in neutral, as most outboards won’t start if the motor isn’t in the neutral position.

Outboard won't start troubleshooting neutral

Outboard No-Start Check 2: Kill Switch

Check the kill switch if your outboard has one, because if it’s been pulled, the outboard won’t start. 

Outboard won't start troubleshooting kill switch

Outboard No-Start Check 3: Battery Switch

Many boats are set up with a main battery switch to preserve battery power when the boat is not in use. If your boat has one, make sure the battery switch is set to the “on” position.

Outboard won't start troubleshooting battery switch

Outboard No-Start Check 4: Battery Cables

Inspect the battery cables first to make sure they’re securely connected. 

Outboard no start troubleshooting battery connections

Next, check for corrosion between the battery posts, the nut and the cables. If you have corrosion, disconnect the cables, clean everything with a wire brush, and use a battery terminal cleaner and protector to shield the connection from the elements.

Outboard won't start troubleshooting battery cables

Outboard starting problems battery cleaning

Outboard No-Start Check 5: Battery Testing

If your motor still won’t start, check to see if the battery is good. Set a multimeter to DC volts, then connect it to the positive and negative side of the battery. You’re looking for a reading of about 12.5 volts, and anything below 12.2 volts is a half-charged battery. If it’s below 12 volts, the battery is pretty much done. 

Outboard no-start diagnosis battery testing

Outboard starting problems diagnosis battery test

Outboard No-Start Check 6: Exhaust

If the battery is good, check the exhaust next. There may be an obstruction preventing the engine from turning over.

Pro Mariner digital multimeter

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Outboard No-Start Check 7: Fuel Lines

Check the fuel lines for kinks that might be restricting fuel flow. Also, make sure there’s fuel in the gas tank and the tank is primed. Otherwise, the motor may turn over but not start. If you can squeeze the priming bulb easily, it means it’s not moving fuel and you may have an obstruction in the line. 

Troubleshooting outboard starting problems fuel lines

Outboard No-Start Check 8: Fuel Tank Vent

Check the fuel tank vent. If it’s obstructed, it’ll stifle the flow, as fuel can’t enter the tank to replace the fuel leaving the tank. 

Outboard won't start troubleshooting fuel tank vent

If you still can’t find the problem with your outboard’s no-start condition, you may be at the point where you can’t iron out your problems at the dock, and your troubles may be mechanical. One of the best diagnostic tests you can do is a compression test. It’ll give you some important clues about where to look inside the engine. Watch the video below to learn how to do an outboard compression test.




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