• 4min

Long-lasting protection for boat engines


Many boat owners often face the same problem: The boat is stationary for a long period of time. If you are not careful, this can quickly become expensive for diesel engines. We will show you what the reasons are and how to remedy the situation.

The typical diesel problem in the marine sector

Due to the significant proportion of biodiesel in modern diesel fuels, winterizing or running boats only rarely is particularly dangerous. Over time, the organic content in the fuel can cause microorganisms such as bacteria, yeasts and fungi to form in the tank and create a kind of sludge. This happens, in particular, when the fuel has a high water content due to moisture or condensation in the tank. A clear case of diesel bug.

However, it is not only bacteria that are problematic, but also resinous residues that occur due to a change in the chemical composition of the diesel fuel during aging. 

The consequence: clogged nozzles and diesel filters. A clogged filter leads to a reduced power output and, in the event of a complete blockage, to a standstill of the engine. Deposits on injectors and nozzles even paralyze the injection system. Such failures will result in serious damage to the engine. And then you have to deal with expensive repairs and extensive cleaning of the tank and the entire fuel system. 

This is noticeable, among other things, by irregular engine running or unusual smoke development.

Long-term protection for diesel engines

Marine Diesel Protect slows down the aging of diesel fuel and protects it against harmful oxidation. In addition, it cleans the fuel system by removing deposits, combating bacteria and thus preventing diesel bug. The entire fuel system is protected against corrosion. The included cetane number booster also makes the fuel more ignitable and completes our all-purpose weapon for the protection of marine diesel.

  • Outstanding aging protection
  • Decontaminates infested tank systems
  • Boosts the cetane number
  • Highly effective
  • Cleans and maintains
  • Active in preventing bacterial infestation

Caution: Take care when using biocides. Take note of the instructions on the label before use.

Problem solver

Is your diesel engine already affected? If the infestation is not yet too advanced, a shock dose may help (increased dosage; see label or application description). 

Nevertheless, the resulting sludge must be extracted from the tank and the diesel filter replaced. Then perform the shock dosing again the next time the tank is filled. This will kill any bacteria remaining in the system and the fuel lines.


Prevention is better! The easiest thing is to move the vehicle regularly. If the vehicle has to be parked up for a longer period of time, it can help to completely empty or fill the tank. This reduces the formation of condensation in the tank. But there is no guarantee that this will stop the diesel bug from spreading!

You can play it safe with the regular use of an anti-bacterial diesel additive. Even a low dose optimally prevents the formation of deposits and bacteria and is considerably cheaper than costly repairs or engine system cleaning.

Our expert tip for decommissioning boats with diesel engines

“After filling the additive, take the boat for a little spin. This will help the additive to also pass through the filter, the pipes and the entire system. All components, including injectors and pumps, will then be protected by the preserved diesel.”

David Kaiser
Head of Research and Development

Long-term protection for gasoline engines

Gasoline can also suffer from fuel aging.

If your 2- or 4-stroke watercraft is stationary for an extended period of time, this can become a problem for your next trip. The aging process in gasoline can lead to reduced ignition readiness, oxidation and corrosion in the entire system. This, in turn, can also lead to expensive repairs. 

With the Marine Gasoline Stabilizer, you protect the fuel against aging and oxidation. It prevents corrosion throughout the fuel system and ensures trouble-free decommissioning. It also stabilizes gasoline fuel with bio-fractions.

  • Simple use
  • With long-term effect
  • Protects the fuel against oxidation and aging
  • Economical due to precise dosing