Like any engine, an outboard motor generates heat while it runs. This heat can be considerably high, which is why motors are designed to deal with the heat in some way, ensuring normal operation can continue without causing damage to the motor or injury to people.
Things don't always work as they should, however, and sometimes engines can get too hot. If your outboard motor is overheating, it's important to work out the problem and deal with it as quickly as possible, but that's not always an easy task. To make it simpler, it helps to understand how outboard motors are kept cool, what can go wrong and how to prevent overheating in the future.
The cooling system
Fortunately for outboard motors on boats, they're surrounded by a substance that's perfect for cooling. Most motors use water to keep themselves cool, constantly pumping it through to ensure a steady supply. As long as this water-pumping system is working fine, there shouldn't be any overheating problems. However, this system is prone to failure from time to time, making it one of the most common causes of overheating.
How to tell if your outboard motor is overheating
Almost all outboard motors have a built-in heat alarm, so if you hear a loud, unexpected warning sound, turn your motor off immediately! If there isn't an alarm, or if it fails to sound, you might also notice an increase in heat that you can feel. The motor might also cut out on its own.
What to check
The first thing you should look at is the water cooling system. Examine both ends — intake and outtake — for any blockages. Things like weeds, sand and mud can easily stop the water from flowing through the motor, but they can usually be cleared easily.
A part called an impeller is responsible for forcing water into the system, but it can sometimes break. It looks sort of like a small cog with protruding teeth. If it does become damaged, not only does it affect the flow of water, but the teeth can enter the motor, which can seriously damage it.
If you can't find fault with either of these things, you should seek professional advice immediately and avoid using the motor again.
The most simple but effective way to prevent outboard motors from overheating is to inspect them regularly. Look for any signs that a blockage may be starting to form, check the impeller for damage, and make sure to change the oil often. Keeping on top of a maintenance routine will ensure your motor has the longest life possible.