outboard motor won't start after running

Outboard Motor Won’t Start After Running – 8 Causes & Fixes


Imagine you’ve got a long day ahead and your outboard motor isn’t in the mood to start. Sometimes it happens even after running quite well. And surely it feels pretty annoying.

But why the outboard motor won’t start after running?

Empty gas tanks, pinched fuel lines, and clogged fuel filters are some of the major reasons. There may be some other reasons for outboard moto to not start. Dead batteries, engines not primed, and blocked air vents can cause the problem as well. However, these problems have some easy solutions.

As far as you’re concerned, these short glimpses may not serve you well. For that, we’ve got you covered with a full-size article. Please have a look further into it for more details.

8 Causes for Outboard Motor Won’t Start After Running

We know you’re always looking for reasons when your outboard motor doesn’t start. That’s why we’ve gathered 8 of them here for you. However, knowing the reasons might not fill your cause all the time. Because you need ideas to fix them as well.

We understand your concern and that’s why we’ve attached some quick solutions alongside the reasons. So, let’s proceed with that.

Cause 1. Faulty Spark Plugs

The key to starting your outboard motor is generating the spark that it needs. And if the spark plugs are at fault, your outboard motor won’t start. The spark plugs may get dirty or damaged for which they might fail to generate the spark. And as a result, the outboard motor won’t start.


Check your spark plugs in case they are gapped improperly. Adjust them properly. Replace the spark plugs if necessary. You can also call in a mechanic to fix the problem if you find it difficult.

Cause 2. Empty Fuel Tank

Well, your outboard motor surely needs fuel to start and operate further. And if there’s no fuel, the motor obviously won’t start. This is a silly yet common reason for your outboard not to start.


Check your fuel tank to make sure there’s enough fuel. Also, keep some extra fuel with you for emergencies. This will help you if you’re out of fuel in urgent moments.

Cause 3. Pinched Fuel Lines

Due to pinched fuel lines, there will be a blockage for the fuel to flow properly. As a result, the engine will fail due to a lack of fuel supply. This can also happen due to clogged fuel filters.

So, even if there’s enough fuel and the spark plugs are okay, the motor won’t start. That’s why this is a reason for the outboard motor not to start.


Make sure there are no loose connections and all the fuel lines are air-tight. Also, keep them neat and clean while servicing. Inspect them regularly so that you don’t face any problems. Clean the fuel filters and replace them if necessary.

Cause 4. Battery Issues

Your battery may get disconnected or the batteries may be dead. The engine won’t get power if there’s no battery connection. As a result, the outboard motor won’t start. That’s why these battery issues are a reason behind the problem.


Check the battery voltage and see if they are okay. Recharge the battery if needed. Look if the batteries are corroded, in that case, you may need to replace them. Also, check the wires that connect the battery with the engine. If the wires are loose or damaged, the battery will get disconnected.

If you don’t know where to find replacing batteries or wires, we’re here to help. We’ve some suggestions for you. Please check them below.

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Hope you’ll find these items useful.

5. Engines Not Primed

Some boats require engine priming before starting. In that case, your outboard motor may fail to start if the engine is not primed. In the case of electric primers, the fuel passing may be improper. Without priming, the engine may fail to power up and the outboard motor won’t start.


Turn the key to on mode and wait while the engine powers up. Make sure the fuel line is okay. Check if there’s any leak that’s causing the fuel line and engine primer to malfunction. Call in a mechanic if you can’t seem to figure out what’s wrong.

6. Blocked Air Vent

Your boat needs adequate airflow and ventilation for proper engine combustion and eventually, start the motor. But if the air vent is blocked, there will be a lack of airflow. This may cause the outboard not to start. That’s why it’s one of the reasons behind the outboard motor not starting.


Keep your air vents clean and check them regularly. Open all the gas tank air vents. Remove any obstructions that can prevent airflow.

7. Safety Features Turned On And Gear Shifting Issues

Many modern boats are equipped with various safety switches on the outboard. Some safety features obstruct the outboard motor to start when in idle condition. So, when you try to start the motor without turning these safety modes off, it doesn’t start. That’s why it’s one of the reasons why your outboard motor won’t start.

Also, your boat should be in neutral gear to start. If it’s shifted to other gears, the outboard motor won’t start.


Make sure to use the safety features properly only when needed. And turn them off while starting your boat.  Also, check the gear lever and shift it to neutral gear if needed.

8. Impurities in Fuel System

There may be water or dirt or gas in the fuel system which can get mixed somehow. And it will prevent your outboard motor from starting. Because the fuel will become impure and it won’t take part in the combustion of the engine.


Check your fuel filtration system as it may cause dirt and water to enter the fuel system. Remove the impure gasses if there are any from the fuel tank. Flush the fuel tank and refill with new fuel. This may solve the problem.

So, these were the 8 common reasons and their solutions behind your outboard motor not starting.


What causes the hard starting of the outboard motor?

Loose connections of the spark plug wires can cause the hard starting of the outboard motor. Also, if the engine is not primed properly, this issue can occur. So, make sure that these things are okay.

Is it necessary for the outboard to be in the water while starting?

Yes, the outboard must be in the water while starting. Or else, it should be connected to a hose supplying water. Without a water supply, the outboard impeller may be damaged severely. So, it’s recommended that you start it in the water.

Can I keep my boat sitting for a few months without running?

Yes, you can keep your boat sitting for a few months. But during this period, you should ensure proper maintenance of the boat. With proper maintenance, you can keep the boat sitting for years or even decades.


Every discussion has an end. And we are at that point of the outboard motor won’t start after running discussion.

Hope you’ll find this article useful enough and utilize the suggestions. Also, be careful enough to maintain your boat well and don’t panic in adverse situations.

That’s all from us this time. Have a great day!

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