Troubleshoot the most common starting problems with outboard engines and other powersports vehicles with our simple guide. Never be stuck at home or on the water again.

Every year many boat owners, recently including my neighbor, experience frustration the first time they get their boat out of storage. You can imagine the choice of words used after the boat is put in the water and it doesn’t immediately start. Outboard engines, as well as other powersports vehicles, need three key items for the engine to run: fuel, air, and spark (ignition). Without these key ingredients, the engine won’t start. If you’re experiencing a starting problem with your engine, we’ll troubleshoot each key item to diagnose the problem and get your boat ready for the season.

Check the Safety Features First

Your boat has safety features designed to keep occupant safety as the priority. They can also prevent outboard engines from starting. Each is very simple to check and easier to fix. Verify each of them before moving on to the other key items:

• Kill Switch – The main power to your engine and accessories will have a kill switch (aka deadman switch) that will turn all electrical power off if it is triggered. Some engines have a cord attached to the switch that is meant to wrap around your wrist and turn off the engine if the cord is pulled. Check that the switch isn’t turned off and the cord isn’t pulled out.
• Neutral Safety Switch – The gear selector for the engine should have a switch to detect if the shifter is in neutral when you try to start the engine. The shifter must be in neutral for the boat engine to start.

Check For Electrical Power and Ignition Spark

It’s fair to assume that if you’ve tried to start your engine, you have power to the starter and boat accessories. If the engine doesn’t start, you can leave the key in the “on” position and check that all lights are working. Working lights indicate the battery isn’t dead, but it still could be low on power. You can confirm the amount of charge in the battery with a multimeter. Charge the battery if it has low power preventing the engine from starting. Check the battery voltage after charging is complete and ensure it is at or above 12.0 volts.

What to Look Out For

The main battery switch should be in the “on” or “both” position to power all accessories. The main fuse should be in operable condition to distribute power. Firstly, check that the battery cables are not corroded from moisture over the storage period. Secondly, check the other electrical connections for loose connectors preventing the power from reaching each circuit. Lastly, check the starter solenoid and starter housing. Ensure that they are making good electrical contact. If they are dirty or corroded, turn the key to the “off” position and clean each electrical connection with a wire brush. You’d be surprised how often bad electrical connections stump the best of us when we’re tracking down a no-start condition.

Next Steps

Once power has been confirmed from the battery to the starter, your engine should start unless you have problems with the ignition points, distributor and coils, or spark plugs. The ignition system has changed over time and become easier to work on for the average owner. Older boat engines may have ignition points that determine when the spark plugs fire in the combustion chamber. Points can become dirty with use, and components can wear out. You can replace the ignition points with a new set. Newer engines will use a distributor cap and rotor to send power to the spark plugs, which also will wear out with use. Each are easily replaced with basic hand tools.

No Spark?

Spark plugs can prevent the engine from starting if they are damaged or dirty. An engine that runs rich will contaminate the electrode and prevent the spark from being produced. The electrode can also wear out with long-term use. I will stop producing a spark to ignite the air and fuel mixture in the combustion chamber. Damaged spark plugs should be replaced with a new set. Some owners will replace the spark plug wires at the same time.

Is Your Engine Getting Enough Air?

Outboard engines don’t operate in a dusty environment like your average powersports vehicle or car engine. This means they won’t normally have an air filter that can become clogged with dirt. Outboard engines use an air box in front of the carburetors or intake manifold and inboard engines use a flame arrestor on the carburetors to prevent the possibility of a fire or bilge explosion. The air box and arrestor can become clogged with debris if left open to the elements while in storage. Rodents can build nests in the air box area that can prevent outboard engines from running. Be sure to clean these areas before you attempt to start your engine.

One additional note on air is checking the exhaust ports on the engine to ensure they are clean and clear. This is another area that rodents will try to build a winter nest, and it can also prevent your engine from starting. You’d be shocked how many acorns can fit in an airbox or exhaust port. My neighbor found out the hard way and had to spend an hour cleaning out fragments of acorns from his engine.

Check Your Fuel System Top to Bottom

The fuel system on your engine can be somewhat complex. It’s best to check each component from top to bottom, or from the fuel tank to the engine. These are the items to check:

Fuel tank

The fuel tank should be checked for cracks that can allow the fuel to drip out and cause a safety hazard. The tank should also be vented to allow air to enter the tank as fuel is used by the engine. Clean or replace the vents if they are not allowing air to enter.

Fuel

An easy mistake to make coming out of storage is to use old fuel. Ethanol-based fuel absorbs moisture and can become saturated if left untreated longer than 30 days. Start with fresh fuel as you attempt to start the engine.

Tank switch

If your boat uses an in-motor and an external gas tank for separate fuel supplies, be sure the tank switch is set to the correct fuel tank.

Fuel lines and connections

Check that your fuel lines are not kinked, leaking fuel, or damaged in any way. Fuel lines can become blocked with debris and prevent the engine from starting after storage. Fuel system connections can use rubber O-rings that will dry out and cause a leak. Replace the fuel lines and O-rings if they prevent the engine from starting or running well.

Fuel filter

The fuel filter is designed to remove dirt and debris from the fuel before it enters the engine. Fuel filters can also collect water in storage and you can see a separation line between the water and fuel inside the filter. Drain the water from the system and replace the fuel filter.

Primer (squeeze) bulb

The primer bulb injects fuel into the carburetor when it is pushed. Most engines require a few pushes on the bulb to build pressure in the system. If the bulb has a crack or leak, the prim bulb will not build pressure. Clean or replace it if the bulb doesn’t become hard after a few pushes.

Electric primer

Newer engines may use an electric primer instead of the manually operated primer bulb to build fuel pressure. You can remove the fuel line after the primer to check if it is flowing fuel to the carburetor. Clean or replace the electric primer if it doesn’t transfer fuel to the carburetor.

Choke

The choke on the carburetor can be manually operated or electric depending on your engine. It is meant to add extra fuel to the carburetor until the engine is at operating temperature. Check that manually operated choke cables aren’t kinked and the linkage is adjusted correctly. Electric chokes should operate on their own, so check they are functioning correctly when cold and warm.

Carburetor and Reed Valves

The carburetor can collect water and dirt in the fuel bowl and jets during storage. You may need to clean the carburetor and adjust the fuel mixture with a small screwdriver if the engine doesn’t immediately start after being in storage. A two-stroke engine will have a Reed valve between the carburetor and engine. The Reed valve prevents the fuel mixture from escaping the engine. If it is damaged it should be replaced.

When to See a Professional

Once the fuel system has been cleaned and checked for leaks, it should start the engine easily. If the engine doesn’t want to start, don’t continue to attempt to start it as it can cause a dead battery. If the engine doesn’t start after a few adjustments, it may be time to seek help from a professional mechanic that specializes in outboard engines and powersport vehicles. Don’t be like my neighbor and spend your weekend fixing your boat at the last minute. Take it to a mechanic ahead of boating season, and enjoy the first weekend on the water.

More Diagnostics for Outboard Engines