Outboard motor will not start

The weather is nice, the drinks are cold, time to go boating! But now your boat's outboard motor won't start. That sucks! In this article, we give some tips to check, and a few solutions.

How does an outboard motor work?

The outboard motor is still a very appropriate choice for a variety of craft. With its compact construction and variety of sizes, they are generally very reliable engines. But sometimes, especially the somewhat older engines refuse service. This can have several causes.

What can you do now?

If the outboard motor won't start, it is often good to start looking at the most simple causes. Some common mistakes;

• Is there really gasoline in sufficient quantity in the tank? Also look inside the tank to see if there is water or dirt at the bottom.
• Is the vent on the tank open? For storage and transport, you can close the vent, but if the engine is running and the vent is closed, the engine will fail.
• Is the gasoline more than a year old? Old gasoline can be a reason for the engine not starting or quickly stalling again. It is better to replace the old gasoline with fresh gasoline then.
• Is the deadman cord in the switch? Otherwise the engine won't start anyway.
• Does the pinch ball in the fuel line stay hard when you squeeze this?
• Is the engine in neutral?

What are the various reasons an outboard motor won't start?

For an outboard motor to run properly, there are a number of conditions that must be met. If they are not, the outboard motor will not start, or will quickly fail again. These conditions are important:

• There must be good fuel in the cylinder
• The air/fuel ratio must be correct
• There must be sufficient compression
• There must be a powerful spark

An empty fuel tank

Of course, with an empty tank, the engine will not start. It may sound like an open door, but check this anyway. The number of times our mechanics have come on site to discover that the tank really is empty after all, despite the tank gauge sometimes indicating otherwise, is unfortunately high. Moreover, completely emptying a tank brings other problems. There is often some contamination at the bottom of the tank. When the tank is completely drained, this is sucked up by the engine and can clog filters.

No good ratio of fuel to air

To achieve proper combustion, air and fuel are needed in a fairly exact ratio. In more modern outboard engines with injection, the engine computer controls it all. But there are

also a lot of engines that still work with a carburetor. This is a mechanical device that also controls the ratio of fuel to air. The adjustment of the carburetor is very important. If the engine keeps running badly, or stalls and then does not start again, it often has to do with the carburetor adjustment. Also, if the choke has to be (partially) pulled out to get the engine to run, this is a point to look at.

A blockage

Sucking up dirt or water, or old gasoline, can also cause blockages in the fuel system. The carburetor is especially prone to this. In a carburetor, there are all sorts of small openings that can become clogged by just a speck of dirt. Have the carburetor cleaned if you suspect this is the problem.

Outboard motor will not start: A malfunction

In addition, of course, there are a variety of parts that can fail, causing the engine to stop starting. Common defective parts are the spark plugs, the ignition module or CDI, the ignition coils and the starter motor.

An overheated engine

Engines get hot and need to be cooled. With a lack of cooling, an engine can seize up and be severely damaged. Want to know more? Then also read 'engine problems with boat cooling.’

Starter motor is stuck

The somewhat larger outboard engines cannot be started by hand. If the engine does not go around at all when turning the key, this may indicate a faulty starter motor. Our mechanics can often diagnose this fairly quickly.

Little compression

In older engines, lack of compression can also be another cause for problems. Due to wear of the cylinders, pistons, piston rings and valves, compression can decrease. Also, cylinders and piston rings get damaged by overheating of the engine. Eventually, this causes the engine to start poorly or not start at all.

Need help?

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