Solving Filtration Problems in Marine Diesel Engines

Several kinds of filtering devices are used in marine diesel engines to keep Diesel Enginesout impurities. Filters and strainers play an important role in ensuring that the fuel supplied to the ship’s engine is free from dirt, debris, and organic particulates. In this blog we shall discuss the various kinds of filters used in marine fuel systems, the commonly faced filtration problems in diesel engines, and the solutions to these problems.

Filtration Devices Used For Marine Diesel Engines

Strainers, mechanical filters, and magnetic filters are the three main types of filtration devices used in marine diesel engines.


A strainer is a crude filter that removes large impurities from engine fuel oil. However, passing diesel engine fuel through a strainer is not enough to ensure that the fuel is clean enough to be used safely by a marine engine.

It should be remembered here that strainers are not an internal component of the fuel system of a marine diesel engine. Instead, they are an external devices used to ensure that the oil being poured into the ship’s fuel tank is free from large impurities that can clog up the intake system.

Mechanical Filters

Mechanical filters are found in all modern marine diesel engines. They are small devices fixed in the fuel delivery system of a ship’s engine that are used to remove small pieces of debris that pass through the strainer.

Mechanical Filters

Magnetic Filters

Magnetic filters are more advanced than mechanical filters and are used to filter out debris and contaminants that contain iron. These particles usually enter the fuel stream when they break away from the walls of the fuel chamber or the metallic pipes that are used to transfer oil from the storage chamber to the diesel engine itself.

Common Filtration Problems

Always keep a spare set of filters on standby. Since filters are continuously used while a diesel engine is working, they experience wear and tear and gradually lose their filtering capabilities.

Without the use of proper fuel filters, the oil input to the main and auxiliary marine diesel engines would not be purified. The unfiltered impurities in the fuel would severely damage the delicate mechanical components inside diesel engines.

Even a tiny piece of sand or organic material can cause a major problem for a marine diesel engine and the fuel injection system if it is not filtered out.

Here are two filtration problems that are commonly faced by boat owners:

Chocked Or Blocked Filter

A chocked or blocked fuel filter can cut off the supply of fuel to a marine diesel engine and reduce its performance. If you notice that your marine diesel engine is providing lesser power than it normally does, there is probably a chocked or blocked filter behind the problem.

The easiest way to clean your engine’s fuel filters is by using a special air blower that is designed for the purpose. You could also hire a professional to manually remove and clean the filter.

Worn Out Filters

Filters have a finite lifespan and they need to be replaced sooner or later. Since manual replacement of filters takes time, you could install a duplex system of filters to take care of the problem.

A duplex filter system has a main filter and a standby one that can be automatically switched on when the main gets blocked. This system is very helpful as it can easily solve your filter problem while you are busy dealing with harsh weather conditions where quick maneuvers are required.

Evernew Marine offers the finest marine engine spare parts for all kinds of ships and boats. Call at +86 21 5107 8032 to learn more about our marine spares.