Author: abmarineservice

A diesel engine on your boat is reliable but can cut out if air gets into the fuel system. This can happen after replacing the fuel filter, when the fuel tank runs dry, or due to a leak in the supply line.

In this blog, you’ll learn step-by-step how to correctly bleed a diesel engine on a boat, so you can get back on the water without a care in no time. A well-maintained fuel system prevents starting problems and extends the lifespan of your engine block.

What you need to bleed a diesel engine

To successfully bleed your diesel engine, you’ll need a number of tools and materials. Here’s a list.

• Spanner or ring spanner (usually 10 or 12 mm, to fit the bleed screw).
• Rag to catch any spilled diesel.
• Drip tray for fuel.
• Manual or electric fuel pump.
• Sufficient extra diesel to refill the system.
• Screwdriver for any hose clamps.
• Torch to better see poorly lit areas.
• Kitchen roll or absorbent cloths for extra cleaning.

Having the right tools will save you time and prevent frustration during bleeding. Also, make sure you’re working in a well-ventilated area so you don’t inhale too many fumes.

A handy step-by-step guide: bleeding a diesel engine

You can easily bleed a diesel fuel system yourself. Follow the steps below carefully to remove air from the fuel system.

Step 1: Check the fuel supply

Check that there’s enough diesel in the tank. Has the tank run completely dry? If so, refill it first and wait a few minutes to allow the pipes to partially fill. Bleeding the system is pointless if there’s no fuel available.

Additionally, it’s wise to check that the diesel is clean. Contaminants like water, dirt, or bacterial growth can block fuel lines and filters. You can check this by collecting some diesel from the line or fuel filter into a clear container. Do you see cloudiness, water droplets, or dirt? If so, it’s advisable to replace the fuel filter first to prevent blockages from causing problems later on.

Step 2: Open the bleed screws

Locate the bleed screws on the fuel pump, filter housing, and injectors. These screws are specifically designed to allow air to escape from the fuel system. Depending on your engine, there may be one or more bleed screws. If necessary, consult your engine’s manual to find their exact locations.

Use a spanner to gently loosen the screws. Usually, start at the fuel filter and work towards the injectors. Be careful not to remove the screws completely; they only need to be opened enough for air to escape. It’s useful to place a rag under the screws to catch any spilled diesel and prevent soiling the underside of your engine bay.

Step 3: Use the priming pump

With many older engines, you’ll have a manual feed pump to push fuel through the system. Operate the pump a few times until diesel flows from the bleed points without air bubbles. This may take a little while, depending on how much air is in the system.

Keep pumping until a steady stream of fuel is visible and check for any fuel leaks at the connections. If you see diesel leaking anywhere, carefully tighten the connections slightly and check again.

Step 4: Start the electric fuel pump (if fitted)

Some engines have an electric fuel pump that primes automatically. In this case, you just need to turn the ignition on and off a few times to fill the system. If in doubt, consult your engine’s manual.

With engines that have an electric fuel pump, this helps to automatically prime the system. Turn on the ignition and let the pump run until no more air is escaping. This process can take a few seconds to a couple of minutes, depending on the length of the fuel lines and the amount of air in the system.

During this process, check for a clear audible difference in the pump’s sound. Initially, the pump might sound gurgling or noisy as air is pumped through the system. As the lines fill up, the sound will become more regular and quieter. This is a sign that the air has been effectively purged from the system.

Some electric pumps switch off automatically as soon as the system is completely filled. If your pump continues to run with an irregular sound or doesn’t draw in diesel, check that there are no blockages or leaks in the fuel lines.

Step 5: Bleed the fine filter and pre-filter

To remove all air from the fuel system, you need to bleed both the fine filter and the pre-filter. This will prevent air bubbles from remaining in the fuel lines, which can cause engine issues.

Locate the bleed screws on the filter housing and the pre-filter. Carefully loosen these with a spanner and wait until a constant stream of diesel without air bubbles emerges. Some systems have a small hand pump on the filter housing to speed up the process. If yours has one, pump it a few times while the screws are open.

Next, securely tighten the bolts again, but not too much. Use finger-tight plus a little extra with the wrench to avoid damaging the threads.

Finally, check the condition of the filters. If the fuel coming out is cloudy, dark, or dirty, it might be wise to replace the filter before proceeding.

Step 6: Bleed the injectorss

If the engine still doesn’t start after bleeding the filters, there may still be air in the lines between the high-pressure pump and the injectors. In this case, it is necessary to bleed the injectors manually. Loosen the fuel lines at the injectors by half a turn using an open-ended spanner. Make sure you have a rag ready to catch any spilled fuel.

Start the engine and let it run briefly. As soon as you see diesel without air bubbles coming from the pipes, tighten them one by one again firmly. Note: Do not overtighten them; hand-tight + a little extra is sufficient.

Let the engine idle for a few minutes after bleeding. This ensures any remaining air bubbles leave the system, and the engine runs smoothly again.

Step 7: Check for leaks

Now that the fuel system has been bled, it’s important to check all bolts and connections for leaks. Even a small leak can cause air to re-enter the system, leading to starting problems or a poorly running engine.

Start the cold engine and let it idle. Using a torch, check for any diesel leaks around the fuel filters, feed pump, fuel lines, and injectors. A dripping or damp connection indicates a fitting isn’t sealed properly. Gently tighten it slightly but be careful not to overtighten the bolts.

Also inspect the fuel hoses for cracks, brittleness, or wear. A worn hose can not only cause leaks but also suck in air, which undoes bleeding the system.

By following these steps, you’ll ensure your diesel engine is properly bled, allowing you to continue your voyage without issue. Any questions? Get in touch with us. We’re happy to help!

Common mistakes and how to avoid them

1. Not bleeding completely

Air can accumulate in various parts of the fuel system. Always bleed all relevant components: feed pump, filter housing, and injectors. Even a small amount of air can cause the engine to run poorly or not start. Therefore, work systematically and do not skip any steps.

2. Not checking the fuel tank

An almost empty diesel tank can draw air back into the system. Always ensure you have sufficient fuel. Also, check the tank for dirt and water, as these impurities can cause serious damage to the fuel system. Consider installing a water separator to protect your engine from moisture issues.

3. Improper operation of the feed pumpn

With a manual priming pump, you often need to operate the lever firmly several times to build up sufficient pressure. If you don’t operate the pump correctly, air can remain in the system, leading to starting problems. Take your time to pump thoroughly and listen carefully to the sound of the fuel flow.

4. Not tightening bleed screws properly

If the bolts aren’t properly tightened, air can get in, causing the engine to run poorly or not start at all. Check all the bolts and tighten them firmly but be careful not to overtighten them to avoid damaging the threads. Use a torque wrench if necessary to maintain the correct tension.

5. Ignoring a clogged fuel filtern

A blocked filter can impede the fuel supply. Check and replace fuel filters regularly to prevent problems. If you notice the fuel is dark or cloudy, it could indicate contamination or bacterial growth in the tank. Consider cleaning your tank periodically and use a fuel additive to combat bacterial formation.

Buy your technical parts from AB Marine Servicee

At AB Marine Service, you’ll find a wide range of parts for your inboard diesel engine. From fuel filters and feed pumps to complete fuel systems, we have everything you need to keep your engine running smoothly. Our experts are happy to help you with expert advice and practical tips to keep your engine in top condition. Order easily online or contact us for more information.

A smoking diesel engine on your boat can be a worrying problem. Not only is the smoke a nuisance, but it often indicates underlying issues with the engine. A quick diagnosis can prevent a lot of damage and costly repairs. Therefore, it’s important to understand what the different types of smoke mean and how to resolve them.

In this blog, you’ll discover the potential causes and solutions for smoke issues, so you can get back on the water worry-free. We also answer frequently asked questions about smoking diesel engines and offer more tips for maintaining your boat’s engine.

Why is my diesel engine smoking?

A diesel engine can smoke for various reasons. The colour of the smoke can tell you a lot about the cause of the problem. Often, a smoking engine is the first sign of a technical fault that, if ignored, can lead to more serious defects. Below, we discuss the most common smoke colours and what they mean.

Keep in mind that diesel engines may naturally produce slightly more smoke than petrol engines when starting from cold or under heavy load. If this is temporary, it’s usually nothing to worry about.

White smoke

White smoke often indicates incomplete fuel combustion or a coolant leak. This can be caused by a cold engine, a faulty thermostat, or injected fuel that isn’t burning properly. A leaking head gasket can also cause coolant to enter the cylinders, producing white smoke and a dropping coolant level. This is often accompanied by pressure build-up in the cooling system. In some cases, you might also notice a milky substance under the oil filler cap or on the dipstick – a sign that coolant is mixing with the oil.

White vapour

White vapour is often mistaken for white smoke, but it’s usually harmless. It’s caused by condensation forming in a water-cooled exhaust, especially when the engine is cold. However, if the vapour persists when the engine is warm, it could indicate a blockage in the water-cooled exhaust or an issue with the engine’s ventilation.

Blue smoke

Blue smoke indicates oil burning and can be caused by worn piston rings, leaky valve seats or a lubrication problem. An oil level that is too high or using the wrong oil can exacerbate this issue, ultimately leading to increased wear on engine components. A faulty turbocharger can also blow oil into the intake, causing blue smoke on acceleration.

Black smoke

Black smoke indicates a fuelling issue. This can be caused by poorly functioning fuel injection, a blocked air filter, or a faulty fuel pump. If the smoke is thick and intense, it can also be a sign of an overloaded engine not getting enough air for efficient combustion. In some cases, black smoke can also result from an incorrect propeller conversion, preventing the engine from reaching optimal revs due to overload.

Grey smoke

Grey smoke is less common but can indicate oil or fuel problems. Often, this is related to a leaking head gasket or an incorrect fuel-air mixture. In some cases, it can also be caused by excessive engine load or a blocked exhaust, leading to inefficient gas evacuation. Grey smoke is sometimes difficult to distinguish from blue smoke; an experienced mechanic can get a better idea of the cause through smell or a compression test.

Common causes of a smoking diesel engine

The causes of smoke vary depending on the colour. Below, we discuss some common reasons. We will be looking out for various signs, such as heavy engine load, worn piston rings, or a dry exhaust.

Fuel problems

Poor or contaminated fuel can lead to incomplete combustion and smoke. Regularly replacing the fuel filter and checking fuel quality is essential. Water or bacterial growth in the fuel tank can affect combustion and damage the injectors and fuel pump.

Poor combustion

Incomplete combustion can occur due to low compression, late injection, or poorly adjusted valves. This can lead to a smoky engine and loss of power. Furthermore, faulty injectors or a worn fuel pump can contribute to inefficient combustion and increased emissions.

Oil leake

If oil enters the combustion chamber, it can cause blue smoke. Worn bearings, a faulty head gasket, or leaking valve seats can be responsible for this. A prolonged oil leak can not only reduce engine performance but also lead to carbon deposits in the cylinders.

Poorly functioning fuel injectors

A faulty injector or fuel pump can lead to excessive smoking and inefficient engine operation. Poor injection can result in fuel droplets that do not vaporise properly, leading to incomplete combustion and increased soot formation.

Problems with the cooling circuit

A faulty thermostat or a coolant leak can lead to white smoke and engine problems. This can damage the engine bay and reduce engine performance. Furthermore, a poorly functioning cooling system can cause the engine to overheat, ultimately leading to severe damage to the cylinders and pistons.

How to fix smoke issues on a diesel engine?

To fix smoke issues, you need to address the underlying cause. Here are some practical solutions.

Maintenance and inspection of the fuel

Check the fuel quality and regularly replace the fuel filter. Use good quality diesel and ensure the fuel pump and injectors are working correctly. Regularly using a fuel additive can help keep injectors clean and prevent contamination.

Adjusting valves and checking valve clearance

Poor compression and valve problems can lead to smoking. Regularly check and adjust the valves. Incorrect valve clearance can also lead to increased camshaft wear and poor engine performance.

Locating and repairing oil leaks.

Check the cylinder head gasket, valve seats, and bearings for leaks and replace any faulty gaskets or worn parts. Persistent oil leaks can lead to excessive carbon build-up and a fouled intake system.

Checking air filter and intake.n

A blocked air filter can cause poor combustion and black smoke. Clean the air filter regularly and check the intake for blockages. A dirty air intake can disrupt the fuel-air mixture and drastically reduce engine performance.

Checking coolant system

A faulty thermostat or leaking coolant can cause white smoke. Ensure the cooling system is working properly to prevent engine damage. Regularly check coolant levels and watch out for any unusual pressure build-up in the cooling system, which could indicate an internal leak.

Buy boat parts from AB Marine Service

At AB Marine Service, you’ll find a wide range of technical Marine parts for inboard engines, drives, and more. Whether you need a new fuel filter, gaskets, or an air filter we offer high-quality products and expert advice.

We’ll help you find the right parts, so your diesel engine runs optimally again, allowing you to take to the water with confidence. Have questions? Don’t hesitate to get in touch. We’re happy to help you find the right product for your problem.

The CV joint on your boat is a vital component of the drivetrain. This coupling ensures that power from the engine is smoothly transmitted to the propeller shaft without jolts, even when the angle of the driveshaft changes. A damaged boot can lead to vibrations, noises, and even damage to your engine or gearbox.

In this blog, you’ll learn all about replacing a CV joint boot on a boat. What are the symptoms of wear? What parts do you need? How do you approach the installation? And where can you buy suitable products?

When should you replace your boat’s CV joint?

A worn or broken CV joint isn’t always immediately noticeable, but there are clear signs. Wear builds up gradually, and if you leave it too late, it can cause considerable damage. We’ve listed four signs that indicate wear and may point to a necessary replacement.

1. You’ll hear a ticking or knocking sound when cornering

One of the first signs of a failing CV joint is a ticking or knocking sound when accelerating or changing direction. This is often caused by play in the balls of the constant velocity joint. The longer you drive with this, the greater the risk of real damage.

2. You’ll notice vibrations or shudders in the drivetrain

If the constant velocity (CV) joint is no longer aligned with the rest of the drivetrain, vibrations will occur. You’ll often feel this in the steering wheel or the boat’s floor. The minimum angle between the engine and the shaft can be disturbed, making the drive unstable.

3. There’s a reduction in performance

If a CV joint is damaged, the connection between the engine and the output shaft can be less effective. Driving force won’t be transmitted properly, causing your boat to accelerate more slowly or reach a lower top speed. If you don’t address this, your CV joint will fail.

4. You see cracks in the dust cover

The rubber boot around the CV joint prevents dirt and water from reaching the moving parts. Do you see grease on the driveshaft or cracks in the boot? If the boot is torn, grease will escape. Loss of grease causes dry friction, leading to increased wear and ultimately a broken CV joint.

What parts do you need?

Replacing a CV joint on your boat requires a number of specific parts and tools. Don’t just think about the CV joint itself, but also about the fitting and alignment.

1. A new CV joint

The core of the job is, of course, a replacement CV joint. It is preferable to choose a high-quality version, such as a Python Drive CV joint. This is known for its reliability and long lifespan.

2. Adapter plate and propeller shaft clamp

For the fitting, you’ll often need an adapter plate to correctly attach the CV joint to the transfer box or output shaft. The set screw clamp ensures everything stays securely in place.

3. Soft engine mounts

When replacing, also check your engine mounts. The correct engine mounts help to dampen vibrations and ensure the engine stays neatly in place during driving.

4. New dust cover and rubbers

The dust cover protects the CV joint from dirt and water. A new cover is often included with replacement, along with the correct seals for a proper fit.

5. Fresh grease

Ensure fresh grease that is resistant to high temperatures and pressure. This will keep the balls in the CV joint well lubricated, extending its lifespan.

6. Bolts, nuts and fixings

New assemblies require robust fixings. Stainless steel bolts and nuts that can withstand the marine environment are preferable. As the drivetrain is subject to vibration, it is advisable to use a thread-locking compound. This prevents bolts from coming loose and extends the life of the fixings.

7. Toolsp

You will need a range of tools:

• Torque wrench
• Spanners
• Allen keys
• Tracking gauge

8. Alignment tools

Correct alignment between the engine and the drive shaft is important. Misalignment leads to excessive wear on both the CV joint and the gearbox. Use special alignment tools or have this carried out by a specialist.

Step-by-step plan: How to replace the CV joint

Replacing a CV joint on a boat is a job you can easily do yourself, provided you prepare properly. We’ll break the process down into seven steps:

Step 1: Check the condition of your current CV joint

Before you start dismantling, check the condition of the CV joint to see if it’s genuinely worn. Look for play, loss of grease, damaged gaiters, and noticeable vibrations while under way.

Step 2: Remove the old CV joint

Turn off the engine, let it cool down properly, and make sure the main battery isolator switch is off. Loosen all the bolts, remove the cover, and carefully pull the CV joint off the output shaft. Tip: have a rag ready for excess grease and dirt.

Step 3: Thoroughly clean the parts

Thoroughly clean the output shaft flange and the connection points on the gearbox. Remove old grease, rust, and dirt. A clean base prevents crooked mounting and unnecessary wear.

Step 4: Apply new grease

Generously lubricate the new CV joint with fresh grease. Use grease suitable for heavy-duty loads and marine applications. Don’t forget the inside of the gaiter and be careful not to get any dirt into the grease.

Step 5: Fit the new CV joint

Fit the new CV joint onto the shaft, secure the gaiter, and tighten the bolts crosswise to the correct torque (preferably use a torque wrench). Also, attach the adapter plate and screw clamp if necessary.

Step 6: Check the alignment

Use a tracking gauge or have a specialist check that the engine and prop shaft are correctly aligned. An incorrect angle can lead to propulsive thrust and extra wear.

Step 7: Test the drivetrain

Start the engine, engage forward gear and check for any vibrations or noises. Preferably, have someone watch during a short test run to identify any deviations early on.

Common mistakes when replacing a constant velocity joint

Replacing a CV joint yourself is quite doable, but some mistakes are lurking. We list five common mistakes.

1. Failing to properly seal the boot

A poorly fitted boot will let in dirt and water, accelerating wear. Always check that the boot is tight and properly sealed with the correct hose clips.

2. Using too little or the wrong type of grease

Grease is essential for the CV joint to function. Use grease that can withstand high pressure and marine conditions. Don’t be stingy: rather a bit too much than just too little.

3. Ignoring worn engine mounts

Worn or torn engine mounts cause engine movement and therefore unnecessary stress on the drivetrain. Check the condition of the mounts before you fit the new CV joint.

4. Not tightening mounting bolts to the correct torque

Too loose? They will vibrate and come loose. Too tight? You’ll strip the threads or damage the flange. Always use a torque wrench and follow the manufacturer’s torque values.

Frequently asked questions about replacing the CV joint

There are always questions about replacing a CV joint. Below, we answer the most common ones.

Can I replace a CV joint myself, or do I need to take it to the ship yard?

Many boat owners do it themselves, provided they have the right tools and parts. If you’re unsure about alignment or correct fitting, leave it to an experienced mechanic.

How long does a CV joint typically last?

That depends on usage, load, and maintenance. On average, 10 to 15 years with normal use and good lubrication.

How much does it cost to replace a CV joint?

The costs vary significantly, depending on the type of constant velocity joint and its application. Standard CV joints are available from approximately €500 to €1,000 for the parts. Python Drive systems start at around €577 (such as the P30-R) but can climb to well over €1,000, depending on the model, axle diameter, and maximum torque. For larger or more heavily loaded systems (like the P80-M), you’ll be looking at thousands of euros.

Always seek expert advice to determine the best type for your boat. Installation costs will be additional if you have it fitted professionally.

How do I know if my CV joint has the correct minimum angle?

Always Check the technical specifications of your engine, driveshaft, and propeller shaft. Systems, such as Python Drive, are designed to absorb angular changes, but alignment remains important.

Is there a difference between car and boat universal joints?

Certainly. A CV joint for a boat is built for heavier and longer-lasting loads, higher humidity, and saltwater resistance. Car CV joints are not suitable for marine use.

Buy your CV joint from AB Marine Service

At AB Marine Service, you’ll find a wide range of technical components for your boat. Among other things, we stock Python-Drive CV joints. Whether you’re tackling a project yourself or need assistance, we’re here to help.

If you want to be absolutely sure you’re choosing the right CV joint, please feel free to get in touch. Together, we’ll ensure your drivetrain runs smoothly and quietly again.

You’re out on the water, enjoying a lovely day’s boating, when suddenly that dreaded little light comes on: the oil light. A low oil pressure warning isn’t something to ignore. Low oil pressure can lead to serious damage to your engine, and you’ll want to avoid that at all costs.

In this blog, we’ll explain what low oil pressure means, how to spot it, and what you can do about it. That way, you’ll know exactly what to do if this problem occurs.

What does it mean if the oil pressure is too low?

Engine oil pressure is crucial for your engine to run smoothly. Engine oil ensures that all the moving parts in your engine remain properly lubricated. This prevents wear and overheating. The oil pressure makes sure the oil gets to where it’s needed.

If the oil pressure is too low, this system will no longer function correctly, with all the associated risks. We will discuss the various consequences of low oil pressure.

Wear of engine parts

When oil pressure is too low, there is insufficient lubrication. Engine parts, such as the crankshaft and bearings, therefore run dry. This leads to increased wear, which causes problems in the long run.

Engine overheating

Engine oil helps to cool the engine too. With low oil pressure, less oil is pumped around, meaning heat isn’t dissipated effectively. This increases the risk of overheating. An oil with a high viscosity maintains pressure better and prevents overheating.

Engine seizure

In the worst-case scenario, lubrication stops altogether. The moving parts then seize up so badly that the engine seizes. This can lead to serious engine damage, requiring an overhaul or even replacement. So don’t wait a few seconds but switch the engine off immediately.

Deterioration in performances

A car with low oil pressure performs poorly. You’ll notice a loss of power and your boat will run less smoothly. This is because internal resistance increases.

Serious damage to the oil pump

If the oil pump fails due to insufficient lubrication or wear, it can bring down the entire lubrication system. The pump is essential for building up pressure and circulating oil. When the filter is clogged, it also affects the pump’s operation.

How to recognise low oil pressure?

It’s important to recognise the signs of low oil pressure early on. This way, you can prevent the problem from escalating and avoid ending up with a broken engine on the water.

The oil light comes on

The most well-known warning sign is the oil warning light illuminating on your dashboard. This notification usually means the pressure has dropped below a certain level. You’ll typically receive a warning for excessively high oil pressure too, but that’s a separate issue. Take this seriously and switch off the engine as soon as you can safely pull over.

Unusual engine noises

When there’s too little oil or pressure, you’ll often hear ticking, dry, or rattling noises. This is because engine components, such as the valves or bearings, are no longer being lubricated properly and are grinding against each other.

Poor engine performance

If you notice your engine is less powerful or struggles to get going, low oil pressure could be the cause. The engine is put under more strain without proper lubrication.

Raised engine temperature

Engine oil normally also helps to cool the engine block. With low pressure, less oil is pumped around, causing the temperature to rise more quickly. So keep a close eye on the temperature gauge.

Smoking exhaust

Blue or grey smoke from the exhaust can indicate oil burning in the cylinders. This can be caused by internal damage or leakage due to a lubrication problem, and therefore also by prolonged low oil pressure.

What can you do if the oil pressure is too low?

As soon as you suspect the oil pressure is too low, it’s important not to continue sailing. Park safely and start with a check. Below you’ll find a step-by-step plan to identify and possibly resolve the problem.

1. Check the oil level

Start at the beginning: is there enough oil in the engine? A low oil level is the most common cause of pressure loss. Top up the oil with the correct type according to your engine’s specifications. Use the dipstick to measure the level. Topping up with the correct type of oil can sometimes resolve the problem immediately.

2. Check the oil viscosity

The oil’s viscosity is important for building up pressure. If the oil is too thin, for example due to age or incorrect specifications, this can lower the pressure. Consider an oil change with a thicker type of oil.

3. Check for leakss

Check around the engine for any oil stains. A leak can cause you to constantly lose oil, leading to a loss of pressure. Pay close attention to the hoses, seals, and the oil filter.

4. Check the oil filter

A blocked filter can impede oil circulation. Replace the filter if it’s old or contaminated. A fresh oil filter helps build the correct pressure.

5. Test the oil pressure sensor

Sometimes there’s no actual low oil pressure, but the oil pressure sensor is faulty. Get it tested or replaced if you’re unsure about the reading. A faulty sensor will give false readings.

6. Check the oil pump

The oil pump is the heart of the lubrication system. If it’s worn or faulty, it won’t be able to build up pressure. In this case, you’ll need to replace the pump.

7. Check the wiring

A poor connection, oxidation or a loose contact can also cause error messages. Visually Check the wiring and use a multimeter if you have one.

8. Have a compression test carried out

If you’ve checked everything and the problem persists, have a specialist perform a compression test. This can reveal internal damage to components such as the pistons or crankshaft.

9. Only Start the engine after checking

Don’t try to “just have a look” to see if the problem’s gone by restarting. This could cause further damage. Only restart after inspection and any necessary repairs.

10. Have regular maintenance carried out

Prevention is better than cure. Regularly changing the oil, replacing the filter in good time and using the correct oil will in many cases prevent oil pressure problems.

Extra tips to prevent damage from low oil pressuren

Always use the correct engine oil

Not all oil is suitable for your engine. Use the correct type of oil recommended by the manufacturer and pay attention to the correct viscosity.

Change the oil on time

Used engine oil loses its lubricating properties. This leads to wear and loss of pressure.

Monitor the operating hours

The age of your engine and its running hours play a part in the likelihood of problems. Older engines are more prone to wear and tear and leaks.

Keep an eye on the oil warning light

Don’t ignore a warning light, even if it goes out after a while.

Buy your boat parts at AB Marine Service

Low oil pressure can have several causes, from a simple low oil level to a faulty oil pump. Whatever the problem, at AB Marine Service, we can help you. We have a wide range of top-quality parts such as oil pumps, sensors, filters, and engine oil.

Our specialists are ready to answer your questions and help you find the right solution. Order easily online or contact us for advice. This way, you’ll keep your engine in top condition and prevent major problems on the water.

Questions about low oil pressure? Let us know. We’re happy to help! 

Replacing the impeller is one of the most crucial maintenance jobs for your boat. Fortunately, replacing the impeller is a job you can easily do yourself. Whether you’re dealing with a worn-out impeller or one that’s broken, this guide will help you step by step.

We cover common issues, provide a detailed step-by-step guide to replacing the impeller, and finish with tips on how to prevent problems. Whether you need a new impeller or just want to know how to change your old one, we’ve got you covered.

Everything you need to know about the impeller

It’s just a small part of your boat, yet an impeller is incredibly important. That’s why we’ll first explain how an impeller works and when replacing it is necessary.

What is an impeller and why is it so important?

An impeller, often made of flexible rubber, is essential for your engine’s cooling system. This rubber impeller ensures cooling water circulates through the engine to prevent overheating. If the impeller breaks or becomes worn, there will be insufficient cooling, potentially leading to serious engine damage.

We obviously want to avoid that. That’s why it’s important to regularly check if your impeller is working correctly and replace it in good time. This way, you’ll prevent problems.

How often should you replace an impeller?

Generally, it’s recommended to replace the impeller every 100 to 200 running hours or at least once a year, whichever comes first. Normal wear and tear on the impeller is inevitable. It happens faster if you regularly navigate in saltwater or heavily polluted water.

Besides, it’s important to look out for signs of wear. For example, blades missing bits of rubber or an impeller that has swollen due to a chemical reaction. In these cases, it’s crucial to fit a new impeller straight away.

Common impeller problems

Using an impeller can lead to a few common problems. Below, we delve into these issues, so you know what to look out for when maintaining your inboard engine.

Worn blades

The constant movement within the pump housing puts a lot of strain on an impeller’s blades. Over time, fragments can break off, chip, or wear away. If an impeller is worn, the motor will still run, but not optimally. Worn blades lead to a reduced water flow. The consequences:

• The engine expels cooling water intermittently.
• The engine increasingly pumps out less cooling water.
• The cooling water temperature is too high.

A broken impeller

An impeller can also break down completely. For example, when running the engine without water. This will burn out the impeller. An impeller can also give up the ghost after prolonged exposure to harmful substances in the water. If pieces of rubber come loose, it can get stuck in the cooling system. This often leads to serious engine damage.

Sticking or swelling impeller

An impeller that has been unused for a long time can become sticky and adhere to the pump housing. If an impeller has swollen, it is often due to a chemical reaction with the water. In both cases, it results in problems with water circulation.

Incorrect assembly

The biggest mistake with an impeller is fitting it in the wrong direction of rotation. This blocks the water flow and will damage an impeller in the short term, with all the consequences that entails. So, ensure the impeller is installed correctly.

Instructions for replacing the impeller

1. Turn off the water valve. Before opening the pump housing, it is important to turn off the water valve. This prevents water from getting into the motor during the impeller replacement and protects you from leaks.
2. Locate the pump housing. On inboard engines, the water pump is usually attached to the front of the engine. It is often a round, metal housing, usually slightly larger than a palm. If you cannot find the water pump directly, you can try following the hoses connected to the cooling system.
3. Open the pump housing. Unscrew the pump housing cover. A small amount of water may escape. After opening the cover, you will see the gasket, a paper ring. Slightly dampen the gasket if it is dry and carefully remove it without tearing.
4. Remove the old impeller. Look at the impeller and note the direction of rotation. It is best not to remove the impeller from the pump housing using two screwdrivers. Pull one of the blades with pliers, or even better: use a special puller for this job. This will prevent damage to the pump housing.
5. Inspect the pump housing. Are there any pieces of rubber from the old impeller? If so, check the pump housing carefully for loose pieces or remnants of the old impeller. Such pieces can block the system and clog the water supply. That is not intended.
6. Install the new impeller. Apply a thin layer of acid-free petroleum jelly to the blades. Then, refit the new impeller. Also grease the edge of the pump housing and the inside of the cover. Ensure you install the impeller in the correct direction of rotation and that the blades drag properly against the walls.
7. Close the pump housing. Carefully replace the gasket and close the pump housing again – with the screws. Be careful not to damage the gasket when screwing. Check that everything is tightened properly to prevent leaks.
8. Open the water valve and test the engine. Check that cooling water is flowing from the outlet. If so, the new impeller is working correctly. Time to get back on the water!
9. Ensure you have a spare. An impeller is and remains a vulnerable part at times. Therefore, ensure you always have a spare impeller on board. This way, you can always resolve an impeller problem.

Replacing an outboard motor impeller

Although we focus on inboard engines, it’s worth noting that outboard motors also rely on a well-functioning impeller for their cooling. The methodology for replacing an impeller in an outboard motor is largely the same.

AB Marine Service primarily focuses on inboard engines, but the principle remains the same: a correctly installed impeller is crucial for engine performance.

How do I buy the right impeller for my engine?

It’s important to buy an impeller that’s compatible with your inboard engine type. Impellers can be made from neoprene, nitrile, or polyurethane, each with its own specific properties and applications.

1. Neoprene impellers. Neoprene impellers are ideal for use in engine cooling systems with both freshwater and saltwater. They offer limited resistance to oil and diesel, making them suitable for applications where contact with these substances is possible.
2. Nitrile impellers. Nitrile impellers, on the other hand, are better suited for bilge pumps and situations involving heavily polluted water. This material is resistant to oil and chemical contaminants, making it ideal for heavy-duty conditions.
3. Polyurethane impellers. Polyurethane impellers are specifically designed for use in a bilge pump, such as those found on boats for wakeboarders. This material offers the durability and abrasion resistance needed to withstand heavy loads from constant water pumping.

To determine which impeller you need, you should check two important things: the brand of the pump and the corresponding model number. If you don’t know the model number, consult the manufacturer’s documentation. This information can often be downloaded from the manufacturer’s website.

Maintenance tips to prevent impeller problems

Maintenance tips to prevent impeller problems If you’ve installed a new impeller, you’ll naturally want it to last as long as possible. That’s why we have some further maintenance tips to prevent new problems with your impeller.

1. Regular inspection. Inspect the impeller annually to ensure it is in good condition. If the blades are hollowed out or missing pieces, these are clear signs of wear. Buying a new impeller is then the best course of action.
2. Check the water inlet. . If the water supply is blocked, it will restrict the water flow to the impeller. Therefore, ensure that the engine doesn’t get clogged with dirt, seaweed, or other obstructions.
3. Rinse the engine after use. After using the engine in saltwater, it’s advisable to rinse the engine with freshwater. This removes salt deposits. This prevents corrosion and extends the lifespan of the impeller.
4. Use acid-free petroleum jelly. When installing a new impeller, it’s important to use acid-free petroleum jelly. This helps keep the rubber supple and prevents the impeller from becoming sticky or adhering to the pump housing.
5. Never start the engine dry. It is essential not to run the engine without water. An impeller runs in water for cooling and lubrication. If you start the engine dry, the impeller can be damaged by overheating within seconds.
6. Avoid long periods of inactivity. Prolonged standing can lead to problems. By sailing regularly, you prevent the impeller from drying out or deforming. Furthermore, the impeller is less likely to become sticky.

Impeller broken? Order your new impeller from AB Marine Service

Replacing an impeller is an essential part of maintaining your inboard engine. By regularly checking the impeller and replacing it annually, you prevent common problems such as a broken impeller or a blocked water supply.

Fancy a new impeller? AB Marine Service is the right place for reliable impellers for all sorts of inboard engines. Feel free to contact us if you need advice. We’re happy to help you on your way.