Starting Boat Engines: A Step-By-Step Guide For Beginners

Starting a boat engine may vary depending on the type and model of the boat and its engine. Inboard engines are typically found on larger boats, while outboard engines are mounted externally on the transom of the boat and are more commonly used. Outboard engines start like a car, but older models are more complex and require more steps to get started. It is important to note that inboard engines should not be started out of water as they require a constant supply of water for cooling, which is drawn from the surrounding water. On the other hand, outboard engines can be started out of water for short periods if proper precautions are taken, such as using a flush muff or motor flusher to supply water for cooling.

Preparing an inboard engine

Inboard engines have more complex systems than outboard engines, and safety is a more significant factor with larger engines on board. Proper preparations and starting procedures can prevent permanent damage from a cold start.

Firstly, pull the engine cover off and check for gasoline fumes, which could indicate a leaking gas line. Check for gas leaks and tighten any fittings. If your engine has ventilation blowers, turn them on and let them run for several minutes to purge all fumes.

Next, use a voltmeter to check the battery for a full charge. Marine batteries can discharge if unattended for a while, especially at the ground connections. Clean the battery posts and cable connections with a battery terminal brush.

Check the fuel filter and, if your craft is equipped with a water sediment bowl, remove and empty it. Replace the fuel filter if the boat has been stored or winterised. Condensation can quickly build up in boat fuel lines and filters, so replacing the filter guarantees no debris or water in the filter elements.

Top off the fuel tank(s) and add a fuel additive to absorb any contaminants and water. Make sure the fuel tank vent cap is clear of obstructions and has the proper venting.

If your boat has been sitting for a long time or has been winterised, drain the oil and replace the oil filter. This will rid the crankcase of any water or fuel that has collected in the engine. You can use an oil evacuation system to remove the oil through the dipstick filler tube, or you might need to unscrew the oil pan drain plug. Drain the old oil into a pan for disposal.

Check the level of the out-drive gearbox fluid and inspect all the grease fittings on the steering arm, motor pivot points, and throttle linkage. The connections should be lubricated, secured, and able to move freely.

If your engine is water-cooled, top off the radiator. The coolant should be clear, with no discolouration or debris. Install the transom drain plug if it has been removed.

Finally, pump the throttle lever two or three times and place it slightly above idle for a start condition. Ensure the boat is in the water so the intake water pump can pick up cooling water. Turn the key and wait for the engine to start and run. Let the engine run slightly above idle for several minutes, then gradually increase the throttle. If the engine runs smoothly without missing, you can launch.

Preparing an outboard engine

Before starting an outboard engine, there are a number of preparation steps to take. First, open the ventilation cap on the fuel tank. This will allow air into the tank as the fuel drains and prevent a vacuum from forming inside the tank, which could damage it. Keep the ventilation cap closed when the boat is not in use.

Next, tilt the motor into the water. On smaller boats, this is done by adjusting the trim, which can be done manually by pulling a pin in the motor bracket. On other boats, there may be an up/down switch on the gear shift. Make sure the propeller is fully submerged.

If your outboard engine has a manual ignition, engage the kill switch. This is usually a lanyard with a 2-pronged metal clip. Wear one end of the lanyard on your wrist, belt loop, or life jacket, and connect the other to the kill switch knob. This is an important safety feature as it will stop the motor immediately if you fall overboard.

Now, squeeze the primer bulb several times to put fuel into the motor. You'll know you're ready when the bulb feels firm and the inline filter is filled with fuel. Check for any leaks in the fuel line connections.

Finally, put the gear shift lever in the neutral position. This will ensure the boat doesn't lurch forward or backward when you start the engine.

Starting an inboard engine

To start an inboard engine, there are several steps you need to follow. Firstly, ensure the boat is in the water and properly secured to a dock or mooring. Check that you have enough fuel for your trip and top up if necessary. It is also important to make sure the battery is charged and connected.

Now you can open the engine compartment and check the oil level. If the oil level is low, add more oil according to the manufacturer's instructions. With the boat in neutral, you can engage the safety lanyard or switch. You are now ready to turn the key and start the engine. If your boat has a choke, engage it until the engine starts.

Allow the engine to warm up for a few minutes before shifting into gear and slowly increasing the throttle. Keep an eye on the gauges and listen for any unusual sounds or vibrations as the boat starts to move. When you are ready to stop the engine, shift into neutral and turn the key off.

Additional Maintenance Tips

There are several other maintenance checks you can perform to ensure your inboard engine is in good condition. Firstly, inspect the engine belts and hoses for any signs of excessive wear or abrasion. Replace any suspect hoses and belts. It is also important to check the fuel lines and hoses for any cracking or signs of wear.

You should also check the propeller to ensure it is not chipped or bent and that it rotates smoothly. If it is in good condition, remove it, lubricate the shaft, and reinstall. It is also recommended to change the engine oil and replace the spark plugs. Finally, check the battery voltage with a multimeter and charge the battery if necessary.

Starting an outboard engine

Preparation:

Before starting the engine, there are a few things you need to do to ensure a smooth process:

• Open the ventilation cap on the fuel tank. This allows air to enter the tank as the fuel drains, preventing a vacuum from forming, which could damage the tank or motor. Keep the ventilation cap closed when the boat is not in use.
• Check the fuel level and ensure there is enough fuel for your trip.
• Adjust the trim of the motor so that the propeller is fully submerged. This makes it easier for fuel to reach the carburettors.
• Engage the kill switch on manual ignition motors. This is usually a lanyard with a 2-pronged metal clip. Wear one end of the lanyard on yourself and connect the other end to the kill switch knob. This is important for safety, as it will stop the motor immediately if you fall overboard.

Starting the Engine:

Once you have completed the preparation steps, you can start the engine:

• Squeeze the primer bulb several times to pump fuel into the motor. Do this until the bulb feels firm, and then check the fuel line connections for leaks. Be careful not to over-pump, as this can flood the motor.
• Put the gear shift lever in the neutral position. This ensures that the boat doesn't lurch forward or backward when you turn on the engine.
• Turn on the choke. This restricts airflow to the carburettor, saturating the air inside with fuel, which helps the motor start, especially in low temperatures.
• Start the ignition by turning the key or pulling the starter cord. If using a starter cord, pull slowly until you feel resistance, then yank it quickly and forcefully. It may take several attempts.
• Once the engine starts, turn off the choke. Driving with the choke on can cause too much fuel to enter the engine, leading to flooding and potential damage.
• Shift the gear lever into forward or reverse, depending on your desired direction.
• Adjust the throttle to the appropriate speed.

Stopping the Engine:

To stop the engine, follow these steps:

• Aim the boat in the direction you want to stop. You will lose steering control as you slow down, so ensure you are heading in the right direction.
• Shift back to neutral.
• Turn off the motor by pushing the stop button or turning the key back and removing it from the ignition.
• Close the ventilation cap and tilt the motor up. This prevents gas from evaporating and excess air from flowing through the tank.

Stopping an outboard engine

Then, shift the gear back into the neutral position. This is an important step to ensure you don't overshoot your mark. If you do, you can always shift to forward for a moment to correct your course. Try not to switch directly between forward and backward gears, as this may cause mechanical damage to your boat.

Finally, turn off the motor. On most models, there will be a red stop button. Simply push it to kill the engine. If you have an electric-start motor, turn the key back and remove it from the ignition.

Additionally, if you are docking or finishing boating for the day, close the ventilation cap on the fuel tank and tilt the motor up. Twist the ventilation cap shut to prevent gas from evaporating or excess air flowing through the tank. Then, adjust the trim to raise the motor so that the propeller blades are out of the water.

Frequently asked questions