Common Causes of Boat Breakdowns

The most common causes of boat breakdowns are often the easiest problems to fix. However, not every issue is an easy fix, nor is every boater handy enough to fix even the smallest of problems.

It’s said that any boating day is a good day, even a bad one, but you might not agree when you find yourself stranded miles offshore with irritated passengers. Packing spare parts and tools is always recommended for emergencies, but most breakdowns are easily preventable with preparation before you even launch. 

Boat engine breakdowns aren’t as simple as car breakdowns, where you can call a tow truck and have your automobile serviced right away. With that in mind, here are some of the most common causes of boat breakdowns and ways to prevent them.

Running Out of Fuel

The number one reason for boat breakdowns surprisingly enough is running out of fuel. You’ll be able to tell this is about to happen if your boat's engine starts feeling sluggish. 

Always check your boat’s fuel level before launching, and keep plenty of extra fuel on board as an extra precaution. Running out of fuel can also occur due to a faulty fuel gauge. So besides filling up the tank before you set sail, make sure the fuel gauge is accurate. Also, keep the “rule of thirds” in mind when using your boat’s fuel: one-third of your fuel supply to go out; one third to get back; and one-third in reserve for emergencies.

Fuel System Issues

Besides lack of fuel, boat breakdowns can also be caused by contaminated fuel. You may have gotten a bad batch of fuel out of the service pump. Bad fuel usually has water or some other contaminant in it that can foul up spark plugs. Contaminated fuel can also corrode fuel tanks, circulate contaminants through the fuel lines and clog fuel filters. Check the fuel filter and the spark plugs often, and add fuel stabilizer to the engine if the boat spends time in storage. It’s also a good idea to bring a spare fuel filter, but if you forgot to bring one, you can probably remove the fuel filter from the engine and clean out any debris to solve the problem.

Dead Battery

Just like in cars, a dead battery is a very common cause of boat breakdowns. A marine battery that’s been sitting around inactive can lose its charge, especially if it was in off-season storage without a smart charger attached to it. Test your boat’s battery periodically to make sure it can still hold a charge and isn’t too old. Corroded terminals can also cause battery failure, so make sure you clean the terminals and connections periodically. If power drain from the battery happens often, consider installing a secondary battery bank on your boat and maybe even a solar panel charger. 

Electrical Failure

Going back to the simplest things, sometimes a boat breakdown is nothing more than somebody accidentally knocking the kill switch out of place. Check the kill switch first, but if that or a dead battery or even a blown fuse aren’t the problem, you could be looking at some other type of electrical failure. 

Electrical problems can range from loose connections to corrosion in the wiring or even a failed ignition switch. Know your boat engine’s electrical system parts and how to clean and inspect them. And at the risk of being redundant, once again, check the simple stuff first before you go digging deeper. 

Inspect the kill switch and the starter switch to make sure they haven’t simply come loose. Make sure to inspect and clean the electrical system wiring periodically. Check the spark plugs too, especially on older outboard engine models, and always carry spare plugs and the tools to change them out.

Broken Belt

A snapped belt is one of the first things to check for if your boat’s engine suddenly stops. Without a working belt, your boat engine’s alternator and water pump won’t work either. A belt snapping will trigger your boat’s engine-overheating warning light. You likely won’t hear the belt snapping over the engine noise, but the light will give you a sign. Another way to tell that the belt has snapped is that the voltage meter will show the alternator not charging.

Inspect your boat’s engine belt for cracks, corrosion and other signs of damage before launching to help prevent a breakdown. Tighten the belt if it’s too loose, and always carry spare belts and the wrenches to replace them just in case.

Engine Overheating

Besides a broken belt, another cause of engine overheating is a lack of water flow in the cooling loop. Most boat motors use the water they’re in to cool the engine, and if that water stops flowing through the cooling system, the engine will overheat. 

Regularly servicing and replacing your boat engine’s water pump impeller is one way to prevent overheating. Check the water pump housing too for damage, as this could cause the impeller to deteriorate. Make sure the coolant reservoir is full, and inspect water intakes and hoses for obstructions, loose clamps and leaks before each launch. If the temperature needle starts to rise, back off of the throttle and let the engine cool down.

Propeller Problems

Boat breakdowns can happen due to problems with the propeller, such as fishing line tangled around the prop. Propeller blade damage can also create problems, especially if the prop directly hit an object that could stop it from turning properly or from working altogether.

While changing a propeller out in the water isn’t ideal, always bring a spare prop and gloves, as well as the tools to swap it out if prop damage occurs. Before something like this ever happens, practice removing and replacing a propeller at home so you can be prepared. 

Transmission Failure

If the shifter isn’t engaging the transmission, a cable from the shift lever to the transmission housing may have become detached. Worse yet, your engine could be experiencing complete transmission failure, and if that’s the case, there’s not a whole lot you can do out on the water. You’ll likely have to wait for help to arrive and bring the outboard to the shop for a costly repair. Transmission failure can mostly be prevented by making sure the fluid or gear oil is fresh and topped off.

Lack of Engine Maintenance

A lack of engine maintenance is guaranteed to eventually cause a breakdown. It’s important you keep up with regular maintenance to avoid getting stranded out on the water. Run through what’s called the 100-hour maintenance service checklist, and when storing your boat for the offseason, make sure to winterize the outboard properly to help prevent breakdowns from happening.