Dyed vs. Undyed Diesel - The Real Story
I've been a petroleum distributor for 15 years and a sailor for the past four years. Here are some facts applicable to diesel fuels sold in Virginia. Years ago, diesel was all the same, known as on-road, off-road, #2 fuel, and home heating oil. It was all clear in color and all high sulfer content. Fuel intended for highway use (On-road) has always had highway taxes added to the price (40.9 cents/gal in VA)and we pay it at the wholesale rack and pass this on to all of our customers (if you are tax exempt and fill out the forms, we don't pass on this tax and we get a refund from the wholesale rack). Truckers/diesel car owners were wise to this and would order home heating oil for their home tanks, fill their vehicles and beat the IRS out of 41 cents per gal. The IRS got wise, now all home heating oil and off-road fuel (for use in road construction vehicles, farm tractors, etc) must be dyed red. If a trucker has red fuel in his tanks, he is busted big time by the IRS for tax evasion. Next, the EPA got into it, they now mandate low-sulfer diesel for all on-road uses (max sulfer content of .5% - a new super low sulfer mandate is coming soon). So now, all the diesel fuel you buy at a gas station is low-sulfer, clear, taxed diesel. All off-road, heating oil, #2 fuel oil is dyed red fuel and allowed to have a higher sulfer content (and does have more engine lubrucity than the low-sulfer fuel). We sell this type of fuel to marinas since marine use is "off road" and road taxes are not applicable. Final twist "they don't make it like they used to". Diesel fuels do not have the stability they had years ago due to the modern catalytic cracking refining processes. It has a shelf life of about six months before it starts to break down and "sludge up", it gets little waxy dark globuals in it as it trys to return to its crude oil origination. You can stop this process by adding an after market fuel stabilizer product. For my nine gallon boat tank - I buy on-road diesel (lower sulfer-less smoke, gas station tanks turn the fuel faster and it hasn't been sitting in the marina storage tank destabilizing for the six winter months), I add fuel stabilizer and anti-bacterial/fungicide additive treatment. Water and dirt particles are the diesel engine's biggest enemies. If fuel gets water in it, bacteria/algae grow in the water and eat the carbon in the fuel stopping up your fuel filters = dead in the water and more sailing fun. Hope this helps,Frank