When you are out on your boat, troubleshooting an issue like engine overheating is not something you want to be dealing with. Unfortunately, like any vehicle, yachts and other large boats with marine diesel engines sometimes have mechanical issues that may require repair and can keep you from enjoying your day on the water. However, that doesn’t have to be the case. Some boat problems can be avoided with some simple maintenance. Other more major problems will require repairs in dock. And some, you may just be able to solve yourself if they strike you while out at sea. By educating yourself on some of the most common boat engine problems and how to fix them, you can get back out to sea more quickly. This article will provide some tips and tricks for troubleshooting boat engine problems you may encounter.

1. Engine Overheating

Engine overheating ranks among the most common boat engine problems you may face. You’ll know your engine is overheating when you see the temperature gauge rising above the normal operating levels. Overheating engines need immediate attention to prevent long-term damage. An overheated engine can catch fire or cause extensive damage to internal components. When you notice your engine is overheating, you’ll want to cut the engine and allow it to cool before performing further boat engine troubleshooting.

When a boat engine overheats, the culprit is most likely the cooling system. Check the system for any blockages and flush the system via the intake to clear it.

Another common cause of engine overheating is impeller failure due to an air lock. Although water will displace most air in the intake lines when you launch your boat, some air will remain in the hose. To prevent premature impeller failure, it’s important to prime the pump by removing the zinc plug and adding some water before you start the engine.

The other problems that could cause overheating are similar to those that you would see in an automobile — the thermostat and coolant levels. Check that the engine has enough coolant. If so, the thermostat may have gotten jammed, requiring a replacement.

2. Boat Starter Problems

An engine that does not start or starts and sputters before dying could have one of several issues. You will likely need to do some troubleshooting of boat electrical problems to find the cause and solution.

The Kill Switch

One simple cause of an engine that turns over but does not start could be the kill switch. Someone may have inadvertently engaged this switch at the helm, keeping the boat’s engine from starting. This is a common cause of boat starter problems. If water pools around the base of this switch, it could short out. You may be able to temporarily disable it to get back to land, but replace the switch as soon as possible to re-enable this safety feature.

Computer Problems

If the kill switch did not cause the problem, you might have a computer problem. Consider how well the engine ran most recently. If you didn’t have a problem during your last run and it occurred within a few days, you probably don’t need to worry about clogged fuel filters or air filters, which can take time and show signs of blockage well before they stop the engine from working.

If you have a modern vessel, the engine likely has an engine control unit, or ECU. Problems with this onboard computer could prevent your engine from starting, even if it worked fine the day before. Check if a wire leading from the ECU has become dislodged. If this caused the problem and you can reconnect the wire easily, you will solve the issue in one step. Otherwise, you will not be able to operate your boat or yacht until you fix the ECU’s problem.

In some cases, you may be able to access the error code from the digital display at the helm. This code will help you determine what problem the ECU has. It may be an error code specific to the manufacturer you must look up in the manual. If you cannot find the code in the manual, look online.

Battery Problems

If you hit the starter button and the engine’s solenoid clicks but the engine doesn’t crank over, the likely cause is problems with your battery. If the rest of the onboard electrical gear works, you know the battery is ok. So what’s the problem? It’s likely one of the batteries has a corroded terminal.

To fix this problem, disconnect both connectors and clean the terminals with a battery post cleaning tool or a wire brush. It’s important to do this monthly during boating season. Leave the battery terminals disconnected and check the engine end of the cables. Remove the hot lead at the starter solenoid, the ground connector from the engine block and the hot lead at the starter solenoid so you can clean the terminals thoroughly.

3. Boat Hydraulic Steering Problems

If your steering does not seem to respond as it usually does or has a lag, your boat probably has air in the hydraulic steering system. These systems often have a bleed screw to allow you to remove the air yourself, with the help of someone at the wheel.

Look for the bleed screw near the rudders and unscrew it slightly to allow air out without removing the screw. Have someone turn the steering wheel in all directions to force air out of the hydraulic lines. Once finished, reseal the screw and top off the hydraulic steering fluid. That should fix your boat hydraulic steering problems.

4. Taking on Water

Taking on water poses a serious problem for those aboard a boat. However, there are some simple potential solutions to this concerning problem.

First, check that the transom drain plug is properly in place. While this seems an obvious step, many people forget it, causing excessive water to seep inside your boat.

Next, shut off the engine and look for damaged or leaking water lines. Coolant or raw water lines may have holes or ill-fitting connections, causing them to leak. Replace the damaged hose if possible.

Next, shut off the engine and look for damaged or leaking water lines. Coolant or raw water lines may have holes or ill-fitting connections, causing them to leak. Replace the damaged hose if possible.

For a very short-term solution, you may be able to tape the hole until you return to shore. Do not go back out without replacing the hose, though.

5. Boat Water Pump Troubleshooting

If your bilge pumps continuously run without pumping out water, you may have a problem with the switch’s installation. The float switch triggers the pumps to start when it floats in water, but if installed incorrectly, it will move upward when your boat moves forward even if you don’t have water that needs pumping out.

Check the location of the float switch. If it faces the front of the boat, someone installed it incorrectly. You will need to reinstall it in the aft position once you return to shore. Next, shut off the engine and look for damaged or leaking water lines. Coolant or raw water lines may have holes or ill-fitting connections, causing them to leak. Replace the damaged hose if possible.

6. Boat Transmission Problems

If you run into problems shifting out of neutral after you’re out at sea, your trip may be ended before it begins.

Many boats use mechanical cable shifts, so the linkage could become physically stuck. Inspect the gearbox for detached transmission cables and reconnect this. Alternatively, if your cable has become stuck with rust or dirt, you can manually wiggle it free.

If your cable isn’t stuck, the problem might be a failed transmission unit. If that’s the case, it likely will need to be looked at professionally. Or if you have the expertise, you can work on it yourself, back on land.

If your boat uses an e-link control, a simple fuse replacement will likely solve the problem.

7. Oil Warning Light & White Exhaust Smoke

If you notice white exhaust smoke and an oil warning light, shut off the engine immediately. The oil level has dropped too low and will damage the components of the engine if you keep it running.

The engine requires oil for lubrication. Without enough lubricant, the metal parts will begin to rub against each other, creating friction heat. This excess warmth is why your engine overheats when the oil levels drop.

Check the oil level in the engine and top it off. Occasionally, a clogged oil filter may prevent oil in a full pan from reaching the rest of the engine. Replace the filter to help keep oil moving through the engine.

These measures should solve the oil warning light problem, but if the engine still puts out dense smoke or makes unusual noises, turn it off and call for help.

8. Excessive Vibrations

The engine does not cause all problems aboard your yacht or boat. In fact, some issues could happen due to debris in the water, causing damage to your boat.

If your boat vibrates during acceleration, instead of conducting boat engine troubleshooting first, shut off the engine and examine the prop. You may have a broken boat propeller.

Snagged fishing line or damage to the prop itself may cause it to vibrate excessively while turning. Remove any visible debris. If you cannot find the cause, you may have a damaged bushing that will need replacement once you get back to shore. Don’t risk running the engine if the prop continues to vibrate.

Shop Diesel Pro Power for Troubleshooting Your Boat Engine Problems

Whether you need a starter switch, Detroit Diesel engine, Cummins engine, twin disc, or some other marine diesel engine part for your issue, Diesel Pro Power has the quality parts you need. We offer 24-hour worldwide shipping where available to get you and your boat moving again as quickly as possible. Our customer care team of experts are happy to assist you anytime with any questions or concerns. Shop Diesel Pro Power today and find out how we can help give you a better boating experience.

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