Nov 10, 2022

by Marc Robic

The fungicide also acts as a biocide and prevents bacteria & fungal growth contamination from growing in your fuel, which is a big cause of filter clogging. The water eliminator, well, it does exactly what is says, prevents water build up caused from condensation in the fuel tank as well as from water that may be present in the fuel where you filled up.

I have a confession to make! I haven’t changed my diesel fuel filters in over 7 years!

Most of us with a diesel engine know that when it comes to engine trouble, 90% of the time, it is usually fuel related. So why do I not change my fuel filters regularly?

It’s simple really. Prevention and use of the right products at the right time. Let me explain.

Most times, any fuel troubles are caused by one or more related problems such as water in the fuel, contaminated fuel, dirty or clogged filters and, finally, damaged or blocked injectors. Maybe a damaged or worn fuel pump.

When I first purchased my current boat, I could not really be sure how the previous owner took care of the fuel systems. Was he careful where he purchased his fuel? Did he change the filters? In the winter, was the boat stored properly with a full tank of fuel and the necessary additives? Is the bottom of the tank made up of a layer accumulated dirt and residue?

So, that year, as soon as the tank was almost empty, I drained and syphoned out the last of the fuel from the tank and changed both fuel filters. I then filled the tank with fresh fuel adding Biobor JF fungicide / biocide (to prevent contamination diesel fuel is known for) and K100 Diesel Fuel Treatment & Water Eliminator. Only a few caps full of each is all you need and I add that amount at every ½ tank refill.

Keep in mind that most marinas north of the snow belt close for the winter and, although they should, many do not refill their fuel reservoirs prior to closing. So, come spring, it is very common to have lots of water from the condensation build up during winter.

Once the boat is out of the water for winter, I top up the tank completely, leaving as little room in the tank as possible. While filling, I stop long enough to add the fungicide and water eliminator, and then finish filing the tank. This is to ensure the additives are well mixed in.

Come spring, I always add a full can of Sea Foam fuel treatment to the tank. Again, all preventative, as the Sea Foam will help keep the injectors and fuel passages clean. One can a year is all I use. (I do the same thing in my cars & lawnmower BTW!)

Some will perhaps see the initial cost of Biobor JF and K100 Diesel as a little high. But consider this; you only use about one or two cap full per fill up. So, these bottles will last you many years. Don’t forget to consider the cost and time of changing the fuel filters you’ll be saving.

The other thing to know, is if you’re travelling for a few days, running the engine long hours and topping the fuel every few days or weeks, you do not need to add any additives as the fuel does not have time to create or grow any contamination. You’re actually purging the entire fuel system as you go.

Just be careful where you fill up! Some marina’s do not sell much diesel fuel and consequently do not keep these tanks full. So, condensation and water in the fuel is a frequent event. When in doubt, add a cap full of K100 Diesel.

If you’re like most and mostly run the engine to get in and out of the harbour, your engine does not have time to really run hot. For that reason, at least twice per season, I take the boat out engine only, set to max hull speed for about an hour. I do that just before the end of season oil change. Plus, diesel engines love to run long and hard, so this will also help keep the engine running clean.

Speaking of filling up, I have one more habit I use every time I refill. I always use a funnel that has a removeable a mesh filter. This is to capture any debris or small dirt particles that may be in the fuel or cannister/jerry can. I always clean it out afterwards and believe it or not, after every refill, there are some particles trapped in the funnel filter. So, proof positive the results are worth the effort!

So again, prevention cost much less time and money then repairs… plus the frustration of breakdowns, which never seem to happen at the right times!

Lastly, full disclosure folks! I do not promote any brands or products nor do I get any income or benefits whatsoever from any products I mention. I only share or mention products I truly do use myself and have that proven themselves during my personal use.

If a product manufacturer or vendor wanted me to test their product, I would do so, but only report the real results I experience and fully disclose their request.

As many people who know me, I prefer supporting local merchants. But here in Montreal, I have found it hard to find Biobor JF and K100 Diesel. Consequently, I do order mine from Amazon. Sea Foam can be found and purchased almost anywhere. Canadian Tire and Home Hardware are sure bets.

Marc Robic
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INFORMATION about the writer:
Marc is a member of the Canadian Power & Sail Squadron. He and his wife, Claude Couture sail their Catalina 270, Aquaholic 3, out of the Ile-Perrot Yacht Club in Montreal, where Marc spent 16 years as Harbour Master. They are regular Caribbean bareboat yacht charterers. With over 40-years experience, Marc is also an avid onboard do-it-yourselfer.

Marc Robic & his First Mate, Claude