Having trouble starting your outboard engine can be frustrating and potentially dangerous, especially if you're out on the water. Fortunately, many common starting problems can be easily diagnosed and fixed with a little troubleshooting. Here are some tips to help you troubleshoot outboard engine starting problems.

Check the Fuel System

Make sure your outboard has enough fuel and that the fuel is fresh. If the fuel is old or contaminated, it can cause starting problems. It is highly recommended to use a fuel stabilizer or ethanol treatment every time you fill up your fuel.  Check the fuel lines and filters for any clogs or damage that may be preventing fuel from reaching the engine.  Also ensure that primer bulbs and hoses are in good condition and not cracked or worn.

Check the Battery

A weak or dead battery can prevent your engine from starting. Check the battery terminals and cables for corrosion, and make sure the battery is fully charged. If the battery is old or damaged, consider replacing it. Using a multimeter, test the voltage of the battery. It should read at least 12 volts. If the battery voltage is low, charge the battery and try starting the engine again.

Check the Spark Plugs

Dirty or fouled spark plugs can cause starting problems. Use a spark plug wrench to remove each spark plug one at a time. Be careful not to damage the spark plug or the threads in the cylinder head. Inspect the spark plugs for signs of wear, damage, or fouling. Look for oil or carbon buildup on the electrode or threads. Worn or damaged spark plugs should be replaced. Use a wire brush to clean any debris or buildup on the spark plug. Make sure to clean the electrode and the threads. Use a spark plug gap tool to check the gap between the electrode and the ground electrode. The gap should be set to the manufacturer's specifications. If the gap is too large or too small, adjust it using the gap tool. Then, reinstall each spark plug in the same cylinder it was removed from. Tighten the spark plug by hand until it's snug, then tighten it an additional 1/8 to 1/4 turn with the spark plug wrench.

Check the Ignition System

The ignition system is responsible for providing the spark that ignites the fuel in the engine. Check the ignition system components, such as the ignition coil and spark plug wires, for any damage or wear. Make sure the ignition system is properly grounded and that the connections are clean and tight.

Check the Starter

If your engine is cranking but not starting, the starter may be the problem. Check the starter motor for any damage or wear, and make sure the starter solenoid is functioning properly.  Check the wiring leading to the starter solenoid for any damage or corrosion. Make sure the connections are clean and tight. To test the starter solenoid, use a screwdriver to bridge the two large terminals on the solenoid. This will bypass the solenoid and send power directly to the starter motor. If the starter motor turns over when the terminals are bridged, the starter solenoid is likely the problem. If the starter solenoid has one or two small terminals, use a multimeter to test the continuity between the small terminals. When the ignition key is turned to the start position, there should be continuity between the terminals. If there is no continuity, the solenoid may be faulty.  Before working on the starter solenoid, it's important to disconnect the battery to prevent any electrical shocks or damage to the system.

Check the Carburetor

The carburetor is responsible for mixing air and fuel to create the combustion necessary to start the engine. Check the carburetor for any clogs or damage that may be preventing it from functioning properly. If the carburetor is dirty or clogged, clean or rebuild it. If you're unsure about how to clean your boat's carburetor, it's always best to consult a professional mechanic.

Check the Compression

Low compression can cause starting problems. Use a compression tester to check the compression of each cylinder. If the compression is low, the engine may need to be rebuilt or repaired. Make sure the engine is warmed up to operating temperature before testing the compression - this will ensure accurate readings. Disable the ignition by removing the spark plugs or disconnecting the spark plug wires, and then remove one spark plug and thread the compression gauge into the spark plug hole. Have a helper crank the engine several times while you observe the compression gauge. Repeat this process for each cylinder.  Record the compression readings for each cylinder. A healthy compression reading should be around 100-150 psi (pounds per square inch) or higher, depending on the engine model and specifications.  Make sure the gauge is securely attached.If you suspect low compression, it's best to consult a professional mechanic to diagnose and fix the problem.


In summary, troubleshooting outboard engine starting problems can be a process of elimination. By checking the items listed above, you can narrow down the possible causes of your starting problems and identify the issue. If you're unsure about how to troubleshoot or repair your outboard engine, it's always best to consult a professional mechanic, or feel free to contact our ABYC-certified experts at (866)388-0390. With a little patience and persistence, you can get your engine running smoothly and safely again.