Dirty Fuel



MarineDiesel’s marine engines are extremely reliable when maintained according to the maintenance schedule detailed in the owner’s manual. However, no engine, regardless of manufacturer, is reliable unless proper care and maintenance is performed regularly. We warranty our products against manufacturing defects, yet, there are always instances where the engines are used in ways never intended, or under conditions that would destroy any engine.

Over 50% of our customers’ mechanical issues come from a single source:


The use of poor quality fuel can be incredibly damaging to modern diesel engines.

Diesel engines manufactured today must comply with strict emissions standards that are emerging globally, but particularly in the EU and USA. Prior to these emissions standards being enacted, dirty fuel was rarely a problem. Indeed, excess carbon or rust would simply be burned in the combustion process. Indeed, on some old, low RPM, two stroke engines, these contaminants could actually be beneficial to the engine.

That is no longer the case.

High performance marine engines require clean, high grade fuel in order to operate properly, and comply with emissions regulations. Unfortunately, the world is not a perfect place, and there are many regions where high-quality fuel is the exception, rather than the norm.

  • Rust, adulteration (water, paraffin), misgraded fuel (intentional or unintentional) are all common problems. In some remote or developing regions, sometimes the assumption to make is that the fuel is contaminated.
  • We have seen owners delay replacing fuel filters as a cost savings measure (far more expensive in the long term)
  • We have seen people running without filters
  • We have seen filters improperly installed
  • We have seen additives that are magically supposed to reduce consumption

All of these factors greatly reduce the service life and reliability of the engine. They also hamper performance more than just about any other factor. The use of high quality filters (Racor or OEM), changed correctly and when needed, is a simple solution that is often overlooked.