How to prolong the life of the motor on a yacht: 15 tips for troubleshooting

This manual is suitable not only for beginners, but also for those who want to operate the outboard motor correctly and for a long time. Of course, some things will seem banal to you, but only because the obvious signals save the engine from a major overhaul. By the way, if you or your friend owns a motorboat- it can be rented out in Ukraine.

Check for fault indicators

Flickering indicators – this is the first call. Light bulbs are sometimes hard to see under the bright sun, so create a shadow and see if they light up. If the light bulb is burned out, then a warning horn can act as an auxiliary fault annunciator. Please note that it may be hard to hear when it is running.

Also, some yachts are equipped with a coolant flow sensor. Keep an eye on this sensor, it will warn you in advance of the need to add antifreeze.

Incorrect thermostat setting

You will not believe it, but in Ukraine even experienced minders can install the thermostat upside down. In this case, the heat-sensitive part is located on the outside, which leads to a rapid overheating of the motor.

Strange engine sounds

If you are deaf, call for help from friends who will listen to the sound of the engine during its start, both cold and hot. For example, a loud exhaust might indicate a low coolant level – the need for water pump diagnostics. “Pig whistle” indicates that the timing belt is loose. Metallic grinding & creaking may indicate that the coolant pump bearing has crumbled. Metallic rattling to the beat of the engine speed means that the valves, lifters or valve rockers are in a deplorable state – need to be replaced.

If it starts only when cold, then there are several options: bent pistons or a bent generator mounting rod that does not fall into the hole for starting it when hot.

Smell in the engine compartment

We understand that not everyone can boast of a good sense of smell after covid, but if you smell burning oil, then you may have overloaded the drive system. If the smell is strong, then oil is leaking on a hot engine. Look around the motor. A sweet smell indicates an antifreeze leak. The smell of burnt hair may indicate a short circuit. The smell of burnt rubber may mean that the water-pump impeller is faulty when running dry (see if the water intake is clogged). This smell can also indicate a malfunction of the sterndrive clutch with insufficient coolant and slipping of the V-belt.

Vibrations on board

There are several variants of the problem: if vibrations are felt only at certain rpm, this may mean that the propeller needs balancing. If the vibrations are only in planning mode, then you have bent a couple of propeller blades. If you experience shaking at all speeds, look at the shaft, it is most likely out of alignment with the motor.

By the way, when replacing a propeller, remember to install a thrust bearing; without it, when the boat moves forward, the propeller hub rubs against the gearbox housing.

Use water-cannons carefully

Always watch for roughness. Some manufacturers still write that there should be less than 1 meter of depth under jet sky. The thing is that water cannons use part of the suction water for cooling, also when sand, small stones, grass gets there, the cooling system becomes clogged and the motors stall.

Manufacturers recommend traversing the familiar shallow at high speed so that the cannon sucks in a cleaner top layer of water rather than scooping up it from the bottom.

Don’t throttle before turning off the engine

We don’t know who is spreading this myth, but the unburned fuel that coats the cylinders forms a sticky coating over time. Trust me, it doesn’t end well.

Buy regulated oil

Or pour a complete branded analogue. Cheap motor-oil shortens the life of the motor. And remember that an oil change will cost you much less than an engine repair.

Don’t disconnect batteries on the move

One day you will burn the fuse diode like this, and then kill the generator. Generator repair is our separate story, but be prepared that the generator manual can take up 300 pages.

Don’t fill up with cheap fuel

Keep in mind that cheap fuel or with a lower octane rating will be able to digest your engine, but not for long. With constant refueling, carbon deposits will accumulate in the grooves of the piston rings and behind the rings. This leads to piston ring sticking, cylinder scuffing, either worse, drive-system seizure. The recipe is simple – fill up at branded gas stations with the recommended fuel.

Mooring lines must not hang from the stern

Sometimes you will definitely not be lucky – at several thousand revolutions per minute thick nylon will be wound around the screw. What’s next? The bearings will be crushed, the seals will be torn, the transmission will lose gears. Do you need it?

And yet, do not be lazy to raise the fenders from the sides and hide them on the bow or stern. Trust me, it’s not just aesthetic.

Sea water corrosion

Recommendation for boats that sail the Black Sea. To protect the connectors from moisture, we recommend treating the electrical connectors with WD-40 or technical petroleum jelly after walking.

Outboard motors after a sea trip require wiping with a cloth with fresh water and coating the walls of the case with a thin layer of oil. Why these spa treatments? So that the motor does not eat from corrosion.

Dilute antifreeze on older engines

It is known that undiluted antifreeze concentrate boils at higher temperatures. Therefore, your engine is running at overheated temperatures, which leads to breakdown.

The engine was running but stalled

You’re having a good time on the water, but the engine suddenly stalls – refuses to start. What should you do?

Usually, the problem is a faulty fuel sensor: either you’ve run out of fuel or the tank level in the tank is so low that fuel-starvation has already begun.

Depending on how easily accessible the tank is, replacing the sensor can be either a simple and quick solution or a repair involving a mechanic.

The engine was running rough before stalling

Did it seem like it was losing power? This is a relatively simple problem – replace the fuel-filter.

The second variant of “rough” operation of the outboard motor can be caused by clogged spark plugs. However, you cannot replace them on the water. The best defense against unforeseen towing assistance on the water is regular, annual preventive maintenance of your engine. 

The engine overheated while riding

The icons on the instrument panel light up, you hear beeps, and the motor goes into “ultra-low power” mode or shuts down completely.

The first thing you should know is that you should NEVER let the engine overheat. Turn it off immediately – let it cool down. While you’re waiting, inspect the water intake, make sure it’s not clogged with grass, reeds, nets, clay, stones, either other debris.

The fact is that most outboard-engines are cooled by water being sucked in, passing through the cooling channels, and then being poured back outside.

If the water-intake-port looks completely clean, turn on it and watch the liquid flow out the back of the boat. If the stream is weak, the clog may be deep inside. In most cases, you’ll have to call a mechanic, but sometimes you can take a piece of wire – thread it through the inlet. Your task is to gently punch through the dirt or leaves. Don’t forget to get the wire out.

If the water-flows evenly and the flow is powerful, check the oil-engine level.

Stains of liquids are visible on the engine

Outboard motors on boats operate in an aggressive environment. Especially if we are talking about marine parking. Gaskets & seals are often the first to fail. They are replaced by a specialized mechanic during scheduled maintenance. Check the seals on the cylinder head, in the lower part, on the steering joints and in the lifting & lowering mechanism. When you return to the yacht club, replace anything that shows signs of wear.