How to Start an Outboard Motor that has been Sitting

Understanding the Challenges of Boat Outboards

Before diving into reviving an outboard that has been sitting idle, it’s essential to understand the common challenges and issues that might prevent it from starting. By being aware of these potential problems, you’ll be better equipped to address them effectively.

1. Fuel system problems: Over time, the fuel in your engine can break down and become less effective, leading to clogged fuel lines, a dirty carburetor, or a malfunctioning fuel pump. Water or other contaminants can also find their way into the fuel system, causing further complications.
2. Electrical system issues: The electrical system can be affected by corrosion or damaged wiring, resulting in a weak or non-functioning ignition system, dead battery, or faulty starter motor.
3. Corrosion and wear: Prolonged periods of inactivity can damage various engine components, such as spark plugs, impellers, and other moving parts. This can hinder performance and make it difficult to start.

It’s important to note that what constitutes a “long period” of inactivity might vary depending on the engine’s age, maintenance history, and environmental conditions. However, an outboard should not be left unused for more than a few months without winterizing, proper storage, and maintenance procedures.

Initial Inspection of the Boat Engine

Before attempting to start your outboard motor, it’s essential to conduct an initial inspection to identify any apparent issues that may have arisen during its period of inactivity. This step will help you determine how to get it up and running again.

1. Visual inspection: Begin by examining the exterior for any signs of corrosion, damage, or wear. Pay particular attention to the fuel lines, spark plugs, and other essential components that may impact the engine’s performance. Check the battery and wiring connections before attempting to get the engine started.
2. Safety precautions: Ensure the engine is securely mounted on the boat or stand before starting the inspection. Disconnect the motor from any power source and ensure the propeller is clear of any obstructions to avoid accidents.
3.  Gather necessary tools and materials: To perform a thorough inspection and subsequent maintenance, gather the required tools and materials, such as a socket wrench, screwdriver, fuel line clamps, spark plug wrench, and cleaning supplies. Having the right tools on hand will make the inspection process more efficient and effective.
4. Inspecting the cylinders and pistons: While examining the exterior, also pay attention to the condition of the cylinders and pistons. Check for any signs of wear or damage, as poor cylinder compression can affect the engine’s performance and ability to start.

Cleaning and Replacing Components

Once you’ve completed the initial inspection, it’s time to clean and replace any components contributing to your engine’s inability to start. This step is crucial for ensuring optimal performance and avoiding further issues down the line.

1. Cleaning the fuel system: Begin by draining any old fuel from the tank, lines, and carburetor. Use a fuel system cleaner to remove any deposits or contaminants that have built up over time. Follow the manufacturer’s instructions for properly using the cleaning solution.
2. Cleaning the cooling system: Remove any debris or buildup from the cooling system, including the water pump, impeller, and thermostat. This will help ensure the boat engine stay cool and operates efficiently once it’s back up and running.
3. Replacing necessary parts: Depending on the condition of your engine, you may need to replace some components, such as spark plugs, fuel filters, or impellers. Consult your owner’s manual or a qualified mechanic for guidance on when and how to replace these parts.
4. Sourcing quality replacement parts: Choose high-quality components from reputable manufacturers when purchasing replacement parts. This will help extend the life of your engine and prevent future issues.
5. Lubricating key moving parts: Apply a marine-grade lubricant to essential moving parts, such as the throttle and shift linkages, to ensure smooth operation and prevent damage.
6. Checking and maintaining the oil level: For 2-stroke and 4-stroke outboards, it’s essential to check the oil level. Consult your owner’s manual for specific instructions on how to do this for your particular motor. Before long-term storage, always remove the spark plugs and oil the cylinders to prevent corrosion and wear.
7. Examining the valves: When cleaning and replacing components, don’t forget to check the condition of the valves. Ensure that they are functioning correctly and are free from damage, as this is essential for maintaining proper engine performance.

Checking the Electrical System

A well-functioning electrical system is crucial for your engine to start and operate correctly. Follow this step-by-step guide to check the electrical system and address any issues you may encounter.

1. Battery condition: Begin by examining the battery for any signs of damage or loose connections. Ensure that it’s fully charged and capable of holding a charge. If necessary, replace the battery with a new one.
2. Ignition system: Inspect the ignition system, including the spark plugs, ignition coils, and distributor (if applicable), for any signs of wear or damage. Clean any corroded connections and replace any faulty components as needed.
3. Cable and wiring connections: Check all wiring connections for signs of fraying or damage. Repair or replace any damaged wiring to ensure a reliable electrical connection throughout the motor.
4. Testing the starter motor: If the engine still doesn’t start, test the starter motor. You may need to replace it or seek professional assistance if it’s not functioning correctly.

Fuel Tank and System Maintenance

Ensuring that your motor’s fuel system is clean and functioning correctly is vital for a successful start after a long period of inactivity. Follow these detailed instructions and tips for maintaining the fuel system.

1. Draining old fuel: Draining old fuel: Begin by draining any old or contaminated fuel from the tank, lines, and carburetor, ensuring the fuel line is properly connected and in good condition. This will help prevent issues caused by degraded fuel or water contamination.
2. Cleaning the fuel system: Use a fuel system cleaner to remove any deposits or contaminants that may have built up during the motor’s inactivity. Follow the manufacturer’s instructions for the proper use of the cleaning solution.
3. Mixing and adding new fuel: Refill the fuel tank with fresh, stabilized fuel. If your engine requires a fuel-oil mixture, mix the fuel and oil according to the manufacturer’s recommendations.
4. The importance of stabilized fuel: Using a fuel stabilizer during storage periods can help prevent fuel degradation and protect your engine from potential damage caused by ethanol-blended fuels.
5. Checking and cleaning the carburetor: Inspect the carburetor for any signs of clogging or damage. Clean it thoroughly, ensuring that all jets and passages are clear. If necessary, seek professional assistance for carburetor repair or replacement.
6. Primer bulb maintenance: The primer bulb plays a crucial role in the fuel system by priming the engine with fuel before starting. Check the bulb for wear, cracking, or damage, and replace it if necessary. Use a primer bulb to prime the fuel system before starting the motor.

Testing the Motor

After addressing the various challenges and performing the necessary maintenance steps, it’s time to test your outboard motor to ensure it’s ready for action. 

1. Safely starting the engine: Before attempting to start the motor, ensure that it’s securely mounted to the boat or stand and that the propeller is clear of any obstructions. Double-check that all fuel lines and electrical connections are properly connected and secure.
2. Observing the initial test run: As the motor starts, pay attention to any unusual sounds, vibrations, or smells that may indicate an unresolved issue. If you encounter any problems, shut off the motor immediately and consult a qualified marine mechanic for assistance in troubleshooting common issues such as carburetor adjustments, flywheel alignment, and ignition system problems.
3. Troubleshooting tips: If the motor still won’t start after addressing the previous steps, consider troubleshooting common issues such as carburetor adjustments, flywheel alignment, and ignition system problems. Consult your owner’s manual or a qualified mechanic for guidance.
4. Monitoring engine temperature and performance: Keep an eye on the engine’s temperature and overall performance during the test run. Overheating or poor performance could indicate unresolved maintenance issues that require further attention.
5. Using a garden hose and muff for testing: If you’re testing the engine on land, attach a garden hose to the motor’s water intake using a flush muff. This will provide a water source for cooling the engine during the test run. Ensure the water flow is sufficient and the engine is not overheating during the test. Check that there is adequate flow out of the telltale.
6. Turning the key and observing the initial test run: When you’re ready to start the motor, turn the key and carefully observe the initial test run for any potential issues. Listen for unusual sounds, vibrations, or smells, and shut off the motor immediately if you encounter any problems.

Long-Term Maintenance for Outboard Motors

To minimize the likelihood of future issues and keep your outboard engine in top condition, it’s essential to practice proper long-term maintenance. 

1. Regular maintenance: Perform routine maintenance tasks such as changing the oil, replacing spark plugs, and checking the fuel system according to the manufacturer’s recommendations.
2. Storing outboards: If you plan to store your outboard for an extended period, take steps to protect it from damage caused by inactivity. This may include draining the fuel system, using fogging oil in the engine, and lubricating moving parts to prevent corrosion.
3. Running the engine during storage: To maintain good condition during storage, running the motor periodically is a good practice, which helps keep the internal components lubricated and prevents the buildup of deposits in the fuel system and other parts.
4. Proper storage conditions: Use a cover or store it in a dry, protected area to shield it from moisture, dust, and debris. Keeping your motor clean and dry will help prevent corrosion and other damage.

Final Thoughts

Maintaining and reviving an outboard motor that has been sitting idle for an extended period requires a thorough understanding of the common issues that can arise, as well as the appropriate steps to address them.

By conducting an initial inspection, cleaning and replacing components, checking the electrical system, and performing long-term maintenance, you can minimize the likelihood of future problems and keep your outboard motor in top condition.

Remember to consult your owner’s manual or seek the assistance of a qualified marine mechanic if you’re unsure about any aspect of the process. With proper care and attention, your outboard motor will be ready to power your boating adventures for years.