Diesel Fuel Water Absorber

Paul · Oct 2, 2004

Doesn't need much

Just follow the directions and you will be OK. It doesn't take much additive to treat anything for diesel. My Bio-Bor direction have me use 1/2 oz of of it for my 30 gallon tank.

John Dawson · Oct 3, 2004

Diesel water absorbers

I read somewhere that water absorbers are a good thing for gas engines, but not so desirable for diesels. Something about sending the water molecules thru the injectors or such. Anyone with more info?

Bill O'Donovan · Oct 3, 2004

Yanmar recommends it

But in very small doses, and only while refueling (to mix it in thoroughly). Go on the Yanmar site for precise figures, something like 1.5 oz per 10 gallons. It really does emulsify the water into the fuel so the water will burn off. I saw it demonstrated at Diesel School.

Gord May · Oct 3, 2004

Mixing Ratios

Over time, most boats will pick up some water in their fuel tanks. Once water is detected either by an engine running rough, inspecting a water separator/filter, or by using a Water Probe Indicator, it should be removed as soon as possible. Other than draining the tank (always a dangerous task), there are several water absorbing products on the market which should alleviate the situation.Fuel Water Absorbers (alcohol / methanol-free) “emulsify” & disperse the water in the fuel, so that it can burn through with no ill effects. See note. Follow the manufacturer’s instructions for absorber/fuel mixing ratios (it doesn't take much).Biocides (Biobor*) kill microbial organisms in the diesel fuel.I’ve also been cautioned against the over-use of both of these products. Notes:Diesel fuel is heavier than gasoline, therefore the volatility (ability to vaporize) of diesel fuel is much lower than gasoline. This lower volatility allows air and moisture to infiltrate the diesel fuel in both vessel and bulk storage tanks much faster than gasoline. Water condensation in diesel fuel storage tanks is a routine problem that must be solved by all users of diesel fuels. The longer the fuel is stored, the larger the problem becomes.Being less refined than gasoline, diesel fuel will hold a much larger amount of water in suspension. This suspended water can cause severe problems with water separators installed on the boat, as well causing the fuel injector tips to explode resulting in extensive repair costs. Because of the much quicker degradation of oxygenated fuel (in some cases 45-60 days), water absorbers are sometimes being used throughout the summer season in parts of the country that use RFG fuel.First, maintain all fuel tanks a full as possible (topped off) to keep condensation to a minimum. Second, purchase fuel from a reliable source to ensure a known quality. Third, filtre the fuel prior to fiolling into tank (*Baja Filtre). Finally, check fuel filler gaskets for damage, and be sure the cap is on and properly tightened to prevent water seepage.

p323ms · Oct 4, 2004

be very careful!!!

A diesel works on the principle of spontaneous combustion under pressure. Alcohol will not spontaneously combust under pressure. Adding alcohol to gasoline can be a good thing in that it raises the octane level. Octane is a measure of resistence to spontaneous combustion and is roughly the exact oppisite of cetane ratings. I have added alcohol to gasoline many times to raise the octane but with a diesel raising the octane is a very bad thing to do. Low octane causes a gasoline engines valves to chatter as the gasoline spontaneously combusts before the piston reaches the top of it's stroke. GM recommends using no emulsifiers with their diesels. They recommend additives that cause the water to separate from the fuel and settle to the bottom of your tank. They say most damage to engines occurs because of emulsification!!!!! Emulsification allows water and other bad stuff to get past the fuel water separator and filters to the engine!!!!! We really need an expert that isn't trying to sell something to explain all of this.

Ed Ryan7037 · Oct 4, 2004

P323ms - Who's selling anything???

I don't believe Gord May is selling anything - he's just offering his usual well informed opinion and advice, which he does often on this board.Gord - Thanks for continuing to chime in on lots of the techincal questions that arise here. I'm sure it's appreciated by most who frequent these pages.

p323ms · Oct 4, 2004

Sorry Gord May

I reread my post and though I wasn't thinking of Gord May a reader might infer that was my intentions. I enjoy reading Gord's posts and respect his opinion. My remark was just a general observation that you often have "experts" that are selling something. Harmless snake oil is no real problem but some snake oils are harmful. Even the biocides can be harmful if added to fuel that already has growth. That growth living or dead will clog up filters and the only real solution is to clean the tank.. The biocides are best as prevention not as a cure. Believing that condensation is how a lot of water gets into your fuel is another harmful idea. If there is a lot of water in your fuel it is coming from some place besides the air. The physics of water/air temperature just doesn't support condensation as a major source of water in a closed tank system. It is a factor in airplanes because they go up to low pressures and temperatures and then they go back down to warm humid higher pressure conditions. Often several times a day. A boat in the water will be cooler during the day and warmer during the night. During the day as temperatures rise the relative humidity will be lower. During the night the water will keep the boat warmer than the air and prevent condensation. I am talking about inside temperatures where most fuel tanks are located. Even in an exposed fuel tank there will be a lag where the fuel is warmer during the evening when the relative humidity is higher. Fianlly even with a huge temperature change there isn't that much change in volume or that much water in air. I am not an "expert" and if my reasoning is faulty I will change my opinions. I too have a diesel and want to keep it healthy!!! I regard these forums as a place to exchange ideas and to come to some kind of "truth". I work as a research scientist and in good science no idea or opinion is sacred and above being questioned. Again Gord May I am sorry if I offended you in any way.Tom

Gord May · Oct 4, 2004

Fuel contamination

Tom:Absolutely no offense taken.I always regret it when deficiencies of time/energy or ignorance (my own) result in incomplete postings (again, my own).Your excellent post illustrates several important points about fuel treatments, filtration, and storage. Thanks! Some further reading:See Practical Sailor’s “Deck-Fill Fuel Filters”:http://www.practical-sailor.com/sample/Fuelfilter.htmlandGood Old Boat’s “ Fuel and water filters: Simple insurance policies” - By Bill Sandifer: http://www.boatus.com/goodoldboat/fuelfilter.htmandFuel Quality - Tank Maintenance (from Octel Starreon):http://www.octel-starreon.com/Technology_Fuel_Quality.htmand“Diesel Engines” - by Dr. Von H. Jarretthttp://extension.usu.edu/files/agpubs/fm07.pdfandSailnet’s “Diesel Fuel Essentials” - by Tom Wood:http://www.sailnet.com/collections/articles/index.cfm?articleid=woodto044Regards,Gord

Fred Ficarra · Oct 5, 2004

You guys are good.

So this explains why I've never had a fuel/water problem except when I left the cap off of the tank during a tropical downpour.

Diesel Fuel Water Absorber

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