Author: abmarineservice

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Water-lubricated propeller shaft leaks

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To function, your ship’s propeller shaft runs from inside to outside, through the hull. Of course, this component is built and installed so that your vessel does not fill up with water, but still, your water-lubricated propeller shaft may leak. Naturally, this is a dangerous situation that you want to prevent or remedy as soon as possible. But how does this arise and how do you fix such a problem? Read on to find out why your water-lubricated propeller shaft is leaking and what to do about it.

Water-lubricated propeller shaft leaks: the cause

There is a difference between a grease-lubricated and a water-lubricated propeller shaft seal. Variants from the first category are easy and low-cost to maintain, but grease replacement is difficult. Moreover, some of this ends up in surface water, which is not environmentally friendly.

A grease-lubricated propeller shaft seal is easily converted to a water-lubricated one. You don’t have to constantly lubricate the grease pot and it is much less polluting anyway. But sand grains are capable of causing considerable wear to the sealing rings. And that, in turn, is the basis for a leak!

Furthermore, your engine may be set up a little too flexibly, meaning the packing rings are not sufficiently able to follow the propeller shaft movements. In addition, a leak may be due to stuffing boxes that seal radially and do not adjust to propeller shaft misalignment. Finally, it is possible that the axle itself may wear out and thus let in water.

Water-lubricated propeller shaft leaks: the solution

The bearings of a water-lubricated propeller shaft installation are made of rubber. These may need to be replaced once in a while to prevent or fix leaks, if you already suffer from leaks.

Do you often sail in waters known to be shallow or sandy for other reasons? Then it’s better to switch to a grease-lubricated propeller shaft. Indeed, as we explained above, that sand is going to affect your seal much faster than you would like. You are much less likely to suffer from that with a grease-lubricated system. The downside is that this requires much more maintenance. That is much less the case with a water-lubricated propeller shaft. But periodically checking that all components are still in full working order can never hurt.

Questions?

That comes in handy, because we have answers! Now if you have a problem with your water-lubricated propeller shaft that is not mentioned here, feel free to contact us . Explain the problem to us so that we can provide you with a suitable solution. Besides just a method, we also have the best parts for you, such as a complete propeller shaft seal, a coupling and a grease cord.. You can easily install these yourself. At AB Marine Service, you can only assume the very highest quality, because we do offer it!

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How to connect a boat alternator

Does the warning light on the dashboard stay lit, or does the battery lack the oomph to start the engine after a while? Time to replace your boat engine’s alternator.

Follow these 3 steps to replace an alternator yourself

  1. Removing the alternator
  2. Buying the correct alternator
  3. Installing the new alternator

Or go directly to:

With conventional dynamos and alternators, one thick cable runs directly from the battery’s positive (Terminal B+) or to the distribution point on the starter motor. 

Turning on the dynamo usually happens via a warning light that visually indicates on the dashboard whether the circuit is complete. As soon as you turn on the ignition, this light will illuminate until the dynamo provides a counter-voltage while running. Does it not illuminate? Then also check the supply to the ignition L, or D+ on the dynamo. You can also simply connect this directly to the earth and see if it then illuminates. 

There are also dynamos that are “mass-free”. This means the entire system is isolated from earth (often the engine block). In this case, these cables must also be disconnected.

The AC signal from the dynamo is often used to drive the rev counter. This is frequently marked on the dynamo as the W terminal. If your rev counter isn’t working either, this is another indication that something is wrong. 

Removing the dynamo


Turn off the electrical system, disconnect the battery or main switch, and check that the voltage is actually off the cables and the charging cable runs to the battery (B+) or distribution point. Disconnect the dynamo’s electrical wires. Mark the disconnected wires so you know where they need to go back later. The dynamo is now free from the electrical system. You can detach it from the engine. Generally, it is attached to the front of the engine with a tensioner and mounting bracket. Sometimes accessibility isn’t ideal, especially in a cramped engine bay, but with some creative socket wrench and extension bar work, you’ll get there. Slacken the V-belt by releasing the tensioner (1&2). Remove the mounting bolt (3).

Dynamo vrij maken van motor
Close-up photo of an alternator

Buying the right alternator for your boat

On our website, you can easily search for the right alternator. The easiest way to find the right dynamo for your boat is by its number. This is often found on the casing with a sticker and/or engraving.

You can also find under the category alternator You can also find it under the category brand and type of the marine engine, or enter the engine type in the search bar. For each starter motor, you will see the dimensions and specifications. The most important measurements are in any case dimensions J1 and J2 (in the drawings C and A) and of course the entire execution of the suspension.

At AB Marine service, you can buy a (replacement) alternator for your specific brand. We have a category page for each brand. Including:

  • Volvo Penta alternator
  • Bosch
  • Delco Remy
  • Denso
  • Duccelier
  • Femsa
  • Hitachi
  • Iskra
  • Lucas
  • Magnetti Marelli
  • Magneton
  • Mande melroe
  • Mitsubishi Motorolla
  • Paris Rhone
  • SEV
  • Valeo
  • Visteon
  • OEM

Also watch our video: How to find the right dynamo for your boat?

Installing the new alternator

Installing the new alternator is the reverse of the steps described above. Ensure all surfaces are clean and free from corrosion. And note that grease is not conductive. Therefore, you should always grease the material after installation. This acts as a protective layer against moisture ingress. For proper protection between the contacts, use contact spray or conductive paste.

Alternator: codes and facts

Installing a dynamo is not complicated if you know what the codes mean. We are in all cases talking about alternators.

L or D+ contact: warning light on the dashboard

In most cases, a ship’s or boat’s alternator functions quite simply. A warning light on the dashboard illuminates when you turn the ignition key. When the engine is running, this light goes out. If the alternator is malfunctioning, you’ll sometimes see the light glowing dimly. This means the alternator has a low output and isn’t providing enough counter-voltage, causing current to flow slowly and the warning light to remain (dimly) illuminated. If the warning light isn’t working, the alternator won’t start either. This connection is often labelled L (lampje/light) or D+ (Dynamo+).

IG or R contact: always voltage for alternator

IG or R Contact is a switched wire from the ignition switch. The wire directly supplies the dynamo regulator with voltage, ensuring it always has voltage to engage.

Eenvoudige L en IG aansluiting met T-stekker
Schematic diagram Simple L and IG connection with T-connector

B+/ A or 30: Output voltage

An output voltage and current from the dynamo go to the battery. Sometimes a diode separator is fitted in between to charge two battery packs separately. You then split the current into two parts, as it were. We usually recommend the use of a battery isolator switch, because it draws less voltage from the charging voltage.

This outgoing voltage wire is often thicker than the others and is generally red. It is designated B+, A, or 30.

Minus sign and G: earth connection

Everything marked with a minus sign or G for Ground means an earth connection and can be connected to the engine or the negative terminal.

W: Tachometer for boat engine

If you have to deal with the tachometer, that is to say the rev counter. The alternator generates alternating current. Each of the coils (usually 3) produces a Hertz signal that increases with the engine speed. The rev counter can convert this signal into an engine speed indicated on the tachometer.

Alternator codes: connection codes per brand

All connection codes per make are shown in the image below. American dynamo models often have a very different coding from Japanese and German variants. However, at their core, the most important and common connections like B+ battery/ D+ lamp and W tachometer are often still present.

dynamo connection code table


Further information about the electrical circuit and testing the installation.

While sailing, the battery is charged by the alternator on the ship or boat’s engine. A battery supplies 12 or 24 volts. If you want more power on board, opt for a larger alternator that supplies more current. In most cases, we can supply an alternator with the same dimensions. Contact us, send us your current setup and as many numbers and details as possible, and we’ll find the right dynamo for you.

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How to replace your boat’s fuel filter

Replacing your boat’s fuel filter is a crucial part of maintaining your diesel engine. This filter prevents impurities, such as dirt and water, from reaching the engine via the fuel. Without a properly functioning fuel filter, you risk starting problems, reduced engine performance, and even serious engine damage.

In this blog, we’ll explain step-by-step how to install a new fuel filter, what tools you’ll need, and how to avoid mistakes. Whether you’re an experienced DIYer or just starting out, this guide will help you get started.

What you’ll need to replace a fuel filter

A good preparation is half the battle. Before you start replacing the fuel filter, make sure you have all the necessary materials and tools to hand. This will not only prevent delays but also minimise the risk of mistakes.

General supplies

For each type of filter, you’ll need the following items.

  • Cloths or absorbent material: Essential for soaking up spilled fuel and keeping your workspace clean.
  • A collection tray: For catching contaminated fuel and any lea.
  • A new fuel filter: Make sure you choose the correct model that fits your engine. Consult the engine’s manual or seek advice from our specialists.
  • Tools: Think screwdrivers, spanners, and filter pliers. These are needed for loosening and tightening the filter.

Specific requirements per filter type

  • Screw-on filters: A filter wrench to unscrew the old filter. If necessary, a rubber sealing ring to ensure a perfect seal.
  • Cassette types: Additional sealing rings. These are often supplied with the new filter, but always check that they are present.
  • Separ filters: A Separ filter is designed to separate water and dirt from fuel and contains a water-repellent filter element. It is important to check whether the filter element is reusable and if specific cleaning agents are required. Additionally, it is advisable to have a spare filter element to hand in case the old filter is full and no longer usable.

Step-by-step guide to replacing a fuel filter

Replacing a fuel filter might seem complicated, but with this structured approach, it’s a job you can do yourself. Below you’ll find a detailed guide per filter type.

Preparation

  1. Turn off the engine: Switch off the engine and wait for it to cool down completely. This prevents fire hazards and minimises the risk of burns.
  2. Work in a well-ventilated area: Fuel vapours can be harmful and flammable.
  3. Turn off the fuel supply: Close the fuel shut-off tap to prevent fuel from continuing to flow through the system during replacement. Check for any leakage at the valve, especially with older fuel lines.
  4. Place a drip tray: Place an oil and fuel-resistant drip tray under the filter to catch any leaking fuel. Use a rag to mop up any small spills immediately.

Replace screw-on filter

  1. Unscrew the old filter: Use a filter wrench to carefully unscrew the filter. Be careful to remove the rubber seal if it has been left behind on the engine, as a seal left behind can cause leaks.
  2. Check the new seal: Smear a thin layer of diesel oil onto the seal. This will ensure a better seal and prevent the filter from being overtightened.
  3. Fill the new filter with clean diesel: If your engine has a mechanical fuel pump, fill the new screw-on filter with clean diesel first. This will prevent air bubbles in the fuel system. (Note: with modern engines that have an electric pump, this is not necessary. With these, it can actually have the opposite effect and send dirt to the injectors. The engine’s manual is the definitive guide for this step.)
  4. Fit the new filter: Screw the filter on by hand until it sits snugly, then tighten it a further quarter turn. Do not use a filter wrench to tighten the new filter, as this can damage the seal.

Cassette types replace

  1. Remove the housing: Use the correct tool (usually a spanner or screwdriver) to carefully unscrew the filter housing and remove the old filter element.
  2. Clean the housing: Use a lint-free cloth to clean the inside of the housing. Avoid harsh cleaning agents as they can damage seals. Check for and remove any old seal rings left inside the housing.
  3. Install the new filter: Install the new cassette filter ensuring the sealing ring is correctly positioned and not twisted. Screw the housing on firmly, but do not overtighten to avoid damaging the seals.

Replacing or cleaning the separator filter

  1. Remove the filter element: Remove the filter element and dispose of the filter and old fuel.
  2. Fill the housing: Fill the filter housing with clean fuel and refit the filter. After refitting, check for fuel leaks at the connections.

Bleeding the fuel system

After replacing the fuel filter, you need to bleed the fuel system to prevent air in the lines from causing engine malfunctions or starting problems. Not all engines have manual bleeding, so check your engine’s manual for the correct procedure.

  1. Check if bleeding is necessary: Some modern engines with an electric fuel pump bleed automatically as soon as you turn the ignition on. Older or mechanical fuel systems need to be bled manually.
  2. Open the bleed screw: Undo the screw slightly until you see fuel emerging.
  3. Manually pump the fuel pump: Keep pumping until there are no more air bubbles in the fuel.
  4. Close the screw: Tighten the screw firmly, but not excessively to avoid damage, and start the engine to check that it runs smoothly.

Common mistakes and how to avoid them

Replacing the filter yourself can be a challenge, especially if you’re unfamiliar with the procedure. Here are some common mistakes and tips to avoid them.

Using the wrong filter

A new fuel filter must always be compatible with your engine. Using an unsuitable filter can lead to leaks or insufficient filtration. Always check the specifications and use an original or manufacturer-recommended filter.

Bleeding the system incorrectly

Air in the fuel system can have serious consequences, such as starting problems or a poorly functioning engine. Ensure you always bleed the system after replacement.

Reusing old seals

When replacing a filter, it is important to also replace the sealing rings. A damaged ring can lead to fuel leakage, which is not only inefficient but also dangerous. Always use a new sealing ring and check that the old ring has not been left behind on the engine.

Tightening the filter too much or not enough

A common mistake is overtightening the filter, which can damage the sealing ring. Conversely, a loose filter can cause leaks. Tighten the filter by hand until it seats properly, then give it an additional quarter turn. Do not use tools to tighten the filter unless specified by the manufacturer.

No preventative maintenance

Ignoring a clogged fuel filter can lead to severe engine damage. Regularly carry out preventative maintenance to extend your engine’s lifespan. Therefore, cleaning your fuel filter is a worthwhile endeavour.

Why a well-functioning fuel filter is important

A fuel filter plays a key role in ensuring your engine runs smoothly. It prevents unwanted particles, like dirt, rust, and water, from entering the fuel and subsequently the engine. If this happens, it can not only reduce engine performance but also lead to serious damage.

Protection against serious damage

When the filter loses its capacity to trap impurities, they can still enter the engine. This can damage the injectors or even lead to damage to the fuel pump. Injectors are highly precise components that are extremely sensitive to dirt and water. A damaged injector requires costly repairs or replacement.

Optimal fuel consumption

When a clogged fuel filter causes reduced flow, the engine has to work harder to draw in fuel. This not only leads to higher costs due to increased fuel consumption but can also result in reduced engine performance, such as a decrease in power and speed.

Longer engine life

A clogged fuel filter can have serious long-term consequences for your engine’s lifespan. If dirt and water enter the engine, they can cause corrosion in the fuel lines and vital components, such as the injectors and fuel pump. Furthermore, these impurities can cause the engine to overheat more quickly or even seize up completely.

How to recognise a clogged fuel filter?

It’s important to know when a fuel filter is getting clogged so you can intervene in good time. Here are some common symptoms:

  • Starting problems: A blocked filter can impede the fuel supply, making it difficult to get the engine going.
  • Reduced engine performance: If you notice the engine is losing power or running unevenly, a blocked filter could be the culprit.
  • Increased fuel consumption: An inefficient fuel system due to a blocked filter causes the engine to use more fuel than usual.
  • Rough idling: When the engine doesn’t run smoothly at idle, it can indicate a blockage in the filter system.
  • Smoke from the exhaust: Excessive or dark smoke can be a sign that the engine is struggling to combust fuel properly due to a lack of clean fuel.
  • Warning light: On some modern engines, a dashboard warning light may indicate that the filter is full and needs replacing.

If you notice one or more of these symptoms, it’s advisable to check the filter straight away and likely replace the fuel filter as a precaution. Want to know how to test when your fuel filter needs replacing? Then read our other blog where we explain when to change a fuel filter.

Replace the boat’s fuel filter yourself

Replacing the fuel filter is a relatively simple job that is important for maintaining the performance and lifespan of your engine. With the right preparation, the correct tools and this comprehensive guide, you can carry out this job yourself.

Do you have any questions or are you unsure which filter you need? Get in touch with our experts. They’ll be happy to help you!

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When should I change the fuel filter of my diesel engine?

When there is water, diesel bacteria (sludge) or dirt (under) in or on the fuel tank, it is time to replace the boat’s engine fuel filter.

Therefore, check the filters of the fuel system regularly. E.g. annually when preparing the boat for winter. Do you see water or dirt in the inspection hole of the filter? Then it is likely that there is also water, diesel bacteria (sludge) or dirt at the bottom of the fuel tank. In that case, replace the diesel fuel filter.

Also read: Slime strings and clogged fuel filters

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How to test and replace glow plugs in the diesel engine of my ship or boat

What are glow plugs?

A marine diesel engine has electric glow plugs that help it start when cold. Diesel engines use spontaneous combustion by compressing oxygen and fuel. Just before the highest pressure is reached and the piston is in the top position, fuel is injected through a vaporiser and the combustion process begins. As the engine can be very cold after not running for a while, it may need a little help. That is where the glow plugs come in. Glow plugs are located in the combustion chamber of the engine and are made of high-grade materials.

Testing a glow plug

To test the glow plug, measure the resistance using a multifunction meter or ohmmeter The wires are to be disconnected before measuring. The exact value of each plug varies, but a defective plug can easily be distinguished from a working one. If a current passes through and the ohmmeter shows a value, it would be fair to assume that the plug is in working order. If it reads infinite, there is an interruption and it would be fair to assume that the plug is defective.

Two types of glow plugs

Glow plugs come in two different types:

  1. Parallel glow plugs

    Parallel glow plugs are connected to earth (engine block) via the entry. The current flows back to the battery via the screw thread. They have one entry and are connected to one another. These are usually the Quick Glow Systems that run on the direct battery voltage.

  2. Serial glow plugs

    Serial glow plugs are working like a light bulb. These are often seen in old systems or spiral filaments. They have an incoming and outgoing wire or connection to the next one. The first plug is the entry and the last one is connected to earth. They work on reduced voltage with pre-heating resistors and a glow eye.

DIY replacement of glow plugs on a marine engine.

Remove any defective glow plugs. NB: they can be very tight, so be very careful, especially when dealing with thin-walled glow plugs. Spray generously with penetrating oil before removal if corrosion has built up around the plugs. Thicker plugs are less particular because of their different diameter and plug ratio.
Keep the area around the opening of the motor clean. Watch the maximum loosening torques (Nm = Newton metre = unit of torque) and the thread size (M).

Tip: also use a torque spanner for loosening.

Maximum loosening torques

  • M8 – 20 Nm
  • M9 – 22 Nm
  • M10 – 35 Nm
  • M12 – 45 Nm

Fitting new glow plugs

When fitting new glow plugs, it would be best to use the tightening moment as prescribed by the engine manufacturer. A little copper grease on the cutting edge and the thread is recommended. Tightening is also done with a tightening moment. They only need to seal. Indication of tightening moments for electrical connections:

  • M8 – 10 Nm
  • M9 – 12 Nm
  • M10 – 15 Nm
  • M12 – 22 Nm

Tightening moment for electrical connections

  • M4 – 2 Nm
  • M5 – 3 Nm

Removal of jammed glow plugs

When the maximum removal torque has been reached, discontinue the loosening effort and do not overstrain. That is because the glow plug may break. And that means dismantling the entire cylinder head. Try to loosen the glow plugs in the following three steps:

  1. Loosening: Spray with penetrating or synthetic oil. Repeat several times during the day and leave it to soak in overnight.
  2. Heat the plug: Expanding and contracting materials may create more play. Tune up the engine or use a power cable to warm up the self-regulating glow plugs and proceed a little longer than usual. Repeat this procedure. Please note: This procedure works only on glow plugs with 11 – 12V operating voltage.
  3. Loosening: Try to unscrew the glow plug once again. Using a suitable tool, carefully unscrew the glow plug in the cylinder head. A long, extended socket wrench often works better than a spanner. This will distribute the force more evenly without the need for straining it sideways. Use a tap wrench to work with both hands. If no luck, repeat the above three steps.
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How to install an inboard engine?

Are you planning to install or modify an inboard engine yourself? Prepare well, start with the basics, and take measurements. With minimal adjustments, you can replace an engine. For recent engines, you often know the installation dimensions or they are easy to find. Pay special attention to:

Make sure to figure out what you need.

Are you still looking for a used engine? Quickly check out our range of used marine engines.

Propeller shaft height

First, check if the engine fits in combination with the propeller shaft height. Is the output of the reverse coupling at the same height as the crankshaft? If the output of the reverse coupling is lower than the existing propeller shaft, the engine will need to be raised.

Engine mounts

On some inboard engines, adjusting the existing engine mounting points is no problem, or the foundation of the steel hull can be modified. In a polyester boat, this becomes more difficult. Therefore, check beforehand if this is possible. Especially with a saildrive, you’re often bound to existing prefab transom fittings.

Maximum tilt

Also check if the inboard engine can handle the maximum tilt while sailing. The maximum tilt is often listed in the manual. A homokinetic drive solves the problem otherwise.


Reverse coupling

The Velvet, PRM reverse coupling, Hurth, ZF, and Twindisc reverse couplings are common reversing couplings. The ratio is often indicated by the engine RPM divided by the output RPM, in a two-to-one (2:1) ratio. Ratio = Two engine revolutions / one propeller shaft revolution (or simply half).

The rotation direction of the output is often indicated as L or R in the 2:1 ratio. L is a two-to-one left-turning reverse coupling for a left-handed propeller.

You may also encounter reverse couplings with an A for angle, for example, in Volvo Penta. These reverse couplings come with a shaft tilted 7 degrees outward. This way, the engine needs to tilt less.

Propeller

Pay attention to the rotation direction of the propeller. There are left-handed and right-handed reverse couplings. The rotation direction of the reverse coupling is indicated when the boat is moving forward and you are looking at the bow.

Be careful with a “Z-drive.” The engine is then reversed, so make sure to check the specifications carefully.

AB Marine Service can perform the power requirement calculation for your boat.

Power

If the power remains in the same direction, you can often reuse the same inlet and outlet connections, such as the exhaust gas outlet, cold water supply, or circulation pipes.

If you are increasing or decreasing the power, check the diameter of the connection on the engine. This is already a good indicator of the required size.

If the exhaust manifold is 45.00 mm, you can use this diameter. Do not go smaller, as it will restrict the engine, leading to potential issues. Going larger is usually not a problem.

Propeller shaft and bearing

Also think about connecting the propeller to the reverse coupling. Some brands are interchangeable, but this is not always the case. You will need an adapter flange. These can be obtained separately upon request or are often supplied ready-made with a homokinetic drive.

If you want to reduce vibration and save time with the connection, consider the advantage of a thrust bearing with a homokinetic drive.

What do you need?

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I have a 12V battery, but the alternator says 14V. What is the difference?

In boats, you have got 6V systems (old, but still common), 12V and 24V systems. The 12V is most common in pleasure cruising and 24V is found in larger ships and inland vessels.

This voltage is energised by the battery, which is recharged by an alternator on the combustion engine. This voltage is higher in order to fill ‘the vessel’ quickly. Without a voltage difference there is no ‘flow’. This creates the confusion between the terms system voltage and charging voltage.

There are also different batteries: starter, traction and semi-traction, sometimes with their own charging value. Real full-traction batteries require a higher charging voltage, always check this when purchasing.

On the AB Marine service site, we use the term ‘system voltage’ as much as possible. A 12V battery must be charged with a 12V alternator. Therefore we use the indication 12V for the alternator. Using the 14V or 13.8V charging voltage as indication would lead to confusion. We supply the alternators standard with a set value for charging starter and semi-traction batteries.

  • 6V calcium battery = 6.9V charging voltage (e.g. vintage car)
  • 12V calcium battery = 13.8V – 14.4V charge voltage (all starter batteries and common semi-traction batteries).
  • AGM semi-traction battery = 14.6V – 14.8V charging voltage
  • GEL battery = 14.2V – 14.8V charging voltage

It is also possible to determine the status of your battery by measuring the voltage, see the corresponding voltages below. Preferably do this a day after charging.

Gebruiksaanw. / Handleiding - Accu Service Holland

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Is your expansion vessel or cooling system running empty?

Is the expansion vessel or cooling system (slowly) losing pressure? It could be a leak in either direction.

First make sure that there is no leak to the outside of the engine. Leaking cooling liquid can evaporate quickly when the engine is hot, which makes it hard to detect. Look for traces of dried cooling liquid. This has usually the colour of the liquid itself: yellow, green or red, depending on the brand and type of liquid. It can easily be fixed by tightening the hose clamp or replacing a cooling water hose.

Sometimes, the leak may show up when using a pressure tester to apply pressure on the system. Also check that the rubber seal of the radiator cap (or expansion cap) is still intact and not worn out.

What if no traces of leaking cooling liquid can be seen?

If the liquid does not run out, it may also escape via the heat exchanger that is connected to the water from outside the vessel. It means that – the other way round – water from outside the vessel enters the cooling system.

As a test, pinch off the outgoing cooling hose from the water from outside the vessel at the exhaust injection elbow. With the engine running, the impeller pump should be building up pressure (no risk of damage) and the cooling system should start filling in case of a leak between the outside water system and the engine heat exchanger. The fluid level in the expansion vessel should rise. That is when it is time to replace the rubber sleeves. The sleeves separate the ”outside water system” from the ”coolant system”.

If all the above is not the case and the motor oil contains no cooling liquid, the engine may also have let cooling liquid enter into the combustion chamber. The cause could be a leaking head gasket or cracks in the cylinder head. Many mechanics cannot determine this fault from the outside for sure. Especially in case of a small leak, this is very unpleasant and hard to assess.

Possible solutions include:

A simple pressure tester (also useful for the first and second step). A low-cost solution, but make sure that the kit comes with the right cap. The tester is also available from AB Marine service, if so required. Alternatively, a nitrogen tester is also a reliable testing tool. It shows when nitrogen from the combustion gets into the cooling liquid. For this, google on e.g. “cylinder head leakage tester kit”.

If you cannot find the cause in steps one and two, remove the cylinder head for further inspection.

Spare parts for the cooling system

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Starting problems? 3 tips to fix.

Here are some tips in the event that you have a battery-related problem or a malfunction in the starting system.

If the engine of your boat has little or no power to start, the starter motor or battery may be defective.First things first: make sure that you have checked the following before you start looking at replacing these parts. Several other things, such as a corroded main fuse, mass switch or soiled electrical connections and poorly connected wiring, may be the cause of a starting problem.

Make sure you are safe before you start working.The engine should only run through the starter motor without starting, so turn off the fuel supply. This can easily be done by using the stop solenoid or by putting the throttle in the stop position. Let’s get the multimeter out and do some testing!

1. Battery check in a few steps!

Step 1: A full battery; set the multimeter to DC (direct current) voltage, connect the red probe to the positive and then the black probe to the negative battery terminal. If the multimeter indicates that the battery output is less than 12 volts, first charge or replace the battery before we continue. At 12.4 volts, the battery is fully charged. Double that figure (24.8 volts) for a 24-volt battery. A few millivolts more or less is okay.

Step 2: Put the multimeter back on Direct Current. Connect the red wire of the multimeter to the positive terminal of the battery, and then the black wire to the negative terminal. Proceed with step 3.

Step 3: Turn the ignition lock to the “Start” position and start the engine, keep it going for about 4 to 5 seconds.Read the voltage as shown on the battery multimeter while starting the engine.The battery is in order if the multimeter reading exceeds 9.5 volts during start-up. A reading of less than 9.5 volts indicates too high a drop in voltage. The cause may lie in a poor chemistry transfer in the battery itself due to age. About time to replace it! Battery in order? Keep on reading.

2. Weak starter.

Since the battery has found to be in order or replaced, it is now time to have a look at the starter motor. Even though the battery was the only problem, the following test may prevent many headaches in the future. Corrosion is a common problem. Check the connections from the battery to the starter itself for any deposits, including the negative terminal. Also check the condition of the connection between the starter and the engine block. This includes disassembly and inspection, but taking measurements could be a faster option in this case. This can be done as follows:

Step 1: Put the multimeter on Direct Current. Connect the red probe to the positive battery terminal and then on the relay connection of the starter, from where the copper cable enters the starter motor. This is the last connection before the + plus disappears in the starter motor itself. Below called the “M terminal”.

Step 2: Turn the ignition lock to the “Start” position and start the engine without running it. Read the voltage as shown on the multimeter while starting.

Step 3: Without drop in voltage between the cable and the starter relay, you should now read 0 volt. But people often read 0.1 volt, and 0.1 to 0.2 volt is no exception for older systems.

It means a voltage of e.g. 12.1 volts starts from the battery, but – due to resistance or a poor contact – ends up at only 12.0 volts. A multimeter measures the voltage difference.So the multimeter will measure a “difference” of 0.1 volt, any number higher than 0 volt indicates resistance. This process can be repeated on the plus terminal for each individual contact and connection, as well as for the negative terminal. That is because every positive electrically charged atom that goes in has to come out again via the negative terminal.

 

Starter meter

Step 4: Add up the values of the measurements in the previous steps. The sum of these values should not exceed 0 to 0.3 volt. The lower the number, the better it is. Just think of it. When starting an ordinary 4-cylinder boat engine, it will run up to 1000 Amps for a short period of time from standstill, after which it will drop until the engine runs at about 200 to 300 Amps. Until the engine runs 1000 Amps with 0.3 drop in voltage, the starter motor will drop 300 Watts. For a standard nominal 1200-Watt starter motor, it means that 25% of the starter capacity is lost. It shows that a minor drop may have major consequences. (example)

3. Conlusion.

First fix the resistance loss and then check that the power of your starter motor is back.
This was about testing the power supply of your starter system. If the starter motor still fails to give full power, it may have an internal defect. In that case, we suggest that you contact one of our specialists for more information about a possible solution.

 

Facts!

R = U / I or Resistance = Voltage / Current or Ohm = Volt / Ampere (Ohm’s law)

P = I * U or Power = Current * Voltage or Watt = Ampere * Volt

Watt = Ampere22 * Ohm
Watt = Volt / Ohm
Ampere = Watt / Volt
Volt = Watt / Ampere

An example with water flowing through a tube gives a better insight into the difference between current and voltage:

Electric charge in volts:pressure of the water in a tube.
Current intensity in Amperes:amount of water per second flowing through a tube.
Resistance in Ohm: thickness of the water tube.
Power in Watt:force of the water against e.g. a paddle wheel.

Click here to read more about replacing the starter motor

Replacing a starter motor yourself? In 3 steps.

 

 

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Why separate electrical systems on board?

How can I properly manage my electrical systems on board?

It’s a comforting thought to have no hassle with the electrical systems on board. How do you ensure that the fridge is cold, the (boat) lighting works, and that you can still start the engine? A battery isolator might be the solution for you.

Charge both the start and lighting battery with a battery isolator (battery separator)

Do you know the sound of a refusing starter motor due to low voltage? Perhaps the lighting, fridge, and other energy consumers have drained the power, and now you can’t start the engine. We recommend a separate lighting and start battery system, such as the Victron Battery Isolator.

Why separate electrical systems on board?

The required power for the lighting system and the starting system differ. The lighting system is often used for long periods, while the starting system only demands high power for short durations. The best solution for this issue is to use two different batteries that are tailored for each system. Fortunately, start and traction batteries are available on the market.

Always a charged battery

Even for a small setup, using a separate lighting and start battery system is advisable. While using power from the lighting battery, there is no connection to the start battery, keeping it full and available for engine starting.

Separate power sources can still be charged with the engine’s alternator

When you separate both power sources, you need to be able to charge them separately. If you want to separate both batteries but still charge them with the engine’s alternator, you use a battery isolator, also known as a diode bridge. The isolator distributes the voltage to both batteries. There are also distributors and separation relays available that switch to the other battery when one is full.

What is a battery isolator?

A battery isolator is a specially designed diode bridge, which connects the second battery (the lighting battery) to the alternator when the engine is running. The relay is controlled by the so-called “D+” connection from the alternator and has a provision to prevent overloading of the alternator and the voltage regulator.

Advantages of a battery isolator

The main advantage of a battery isolator is that there is an absolute separation between the battery sets under all circumstances. If one of the two batteries is empty, it can never transfer the power. Think of two barrels of water. A battery isolator conducts the charging current from the alternator or battery charger and distributes it to both battery sets. This is done through two or more diodes, which act as a “check valve” for the charging current. There is only one direction for the current, and it cannot flow back. We offer a range of simple battery isolators to realize the above system. Always check the voltage and required power that can go through the relay.

NB: You can also charge the battery with a battery isolator from the regular 230V power grid.

How many volts per relay?

The rule of thumb is as follows:

  • 70 AMPERE DIODE BRIDGE: for battery chargers and alternators up to 55 Ampere maximum charging current.
  • 120 AMPERE DIODE BRIDGE: for battery chargers and alternators from 60 to 90 Ampere.
  • 150 AMPERE DIODE BRIDGE: for battery chargers and alternators from 100 to 120 Ampere

Battery isolator with compensation diode

Note that a diode always has a bridging voltage (threshold voltage) of 0.6 volts. This means that with a 14V charging system, a maximum of 13.4V will go to the battery. This can be a problem with older types of alternators. An isolator with a compensation diode prevents voltage drop across the diode, ensuring the battery is charged with the correct voltage.

Setup of a battery isolator

See the diagram for a simple setup of a battery isolator:

battery isolator

Buy a battery isolator (battery separator)

Click for a affordable battery isolator for your boat!