Where do they come from?

A simple way to troubleshoot the system is to install a vacuum gage between the filter and the engine lift pump, and a shut off valve on the inlet of the filter. Perform a test that we call the operational test or pre departure check, start the engine and let it warm up, shut off the fuel supply to the primary filter and let the vacuum gage increase to around 10″hg, now shut down the engine and watch the vacuum gage to see if the needle has changed after 5 to ten minutes. If the needle stands at the reading it was when the engine was shut down then the system is tight. If the vacuum gage needle moves towards zero, there is most likely a leak at one of the connections. Now if you want to check the fuel system from the fuel tank to the engine do the same test but shut off the fuel at the tank shut off.  The most common areas for trouble are at the engine connections where there is a high amount of heat, vibration, and/or hose barb type connections. The fuel filter is an another area that must be checked for rolled o rings, loose fittings or valves. Always check any pipe thread connection for proper thread sealant (not thread tape).

It’s all around us and also in your fuel system. The quality  of today’s diesel fuel  has not advanced. In fact it’s deteriorated. Today’s diesel fuel contains more asphaltene solids and water than the fuel of just a few years ago.

Alphaltenes are components of asphalt, that are generally insoluble and are present to some extent in all diesel fuel. These black tarry asphaltenes are hard and brittle, and are made up of long molecules. Fuel with a high percentage of asphaltenes affect  the engine performance by reducing the ability of the fuel to burn completely. Asphaltenes also shorten the life of the primary and secondary fuel filers. Water is the greatest concern because it is the most common form of contaminant. Water is introduced into the fuel system by pumping fuel with water in it all ready, condensation, leaking deck fill o-rings. The effects of water in the diesel fuel can be serious. Water can cause the tip of the injector to blow off, reduce the lubricity of the fuel which can cause seizure of the close tolerance assemblies such as plungers. Water that enters the combustion chamber can result in even more serious damage. When water comes in contact with the heat of the combustion chamber it turns to steam and often explodes the tip off the injector or over pressurize the chamber and cause structural damage to the combustion chamber. Water causes corrosion in the injection fuel system, fuel storage system, and reduces combustibility. It is estimated that eight out of ten diesel engine failures have been directly  related to poor quality and contaminated fuel. The buildup of contaminants in the engine fuel system and storage tanks can quickly clog filters, resulting in engine shut down, fuel pump wear, diesel engine damage.

How many time have you heard about the boater that left the dock after fueling or sat in an anchorage for months and the engine shut down when they left port due to water problems?

You asked, and I wrote!

I just got back from the Annapolis boat show, where I had the opportunity to meet with many of you cruisers! Thanks for stopping by!

For those who didn’t have the chance to make it to the show, I kept note of what the most frequent concerns were so that I could address them here.  Most boaters I spoke with were concerned about their diesel fuel systems because they had dealt with a fuel problem in the past. The most common reasons were as follows:

1. Contamination – (Microorganisms, Dirt, etc)

1. 2. Water

1. 3. Air Leaks