CONTAMINATED FUEL/ WATER IN FUEL

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      CONTAMINATED FUEL/ WATER IN GAS PART 1 

        Contaminated fuel is like a dog with a bone it will not give let go!

 It will give you more motor running problems then you can imagine! Quite often when you think that you have beat the issue, the contamination is all gone, then mechanical failures show up. Contaminated fuel will come back to get your motor again and again. So how does the fuel get contaminated with water and other debris, and what are the effects to your boat motor?

First off lets discuss how this contamination can happen:  Gas caps and the fuel vents are the first common sense place to look for a point of  water entry into your gas tank. When you look at power boats there are generally two different types of fuel caps.

 

The first type of fuel cap is the self venting cap. This is a filler cap that includes a built in vent. The vent allows the tank to expand and contract with temperature variations. The vent also allows the tank to expel air during the filling process and allow air to enter the tank while the fuel is being consumed.

*This type of cap quite often has a large inside rubber gasket that seals off the filler pipe when closed while leaving the vent to be able to breath air for expansion and contraction and varying fuel levels. In many cases were the fuel in the tank has become contaminated the gasket which seals the filler pipe is damaged or missing. Meaning that in the rain or while washing your power boat the water can pass the cap and enter the filler pipe, down the filler hose to the fuel tank.

*The second type of fuel cap is the screw type fuel filler cap: These caps generally require a deck key to open them. The cap threads into the filler pipe. There are two major issues with this type of cap one there is a rubber o ring that creates a seal under the cap lid which maybe missing or damaged. The filler cap maybe deck mounted in such a fashion that rain water or wash down water may pool on top off the cap.Giving the water lots of time to work past the cap and enter the tank.

*The fuel vent: The fuel vent is mounted on the hull side and is used in conjunction with a non vented fuel filler cap. The vent could be turned so that the air opening is facing in a direction were when either running the boat, while raining or washing the water may enter the vent and thus get into the tank through the fuel tank vent line.

                   The other factors that may allow water to enter the fuel tank are:

Environment VS Volume of fuel in tank;  This means that if the volume of fuel is never topped up and or the boat lives in an area were the temperature can make large swings the fuel tank can sweat thus water will build up over time. (This also occurs when the boat has been stored for lengths of time without use).

Please keep in mind that current fuels that contain methanol will absorb water, compounding the problem.

You may have purchased contaminated fuel at the fuel provider. What can also happen at a full serve gas dock is that the attendant mixes up which cap is which and water is accidentally added to the fuel or visa versa were fuel ends up in the water. Any Power Boater who has been around awhile has seen this happen.

Off course there is always the possibility that the contamination is from the tank fitting themselves there are bad signs that go along with this issue, the primary sign is that there is an issue with tank fittings failing is the smell of fuel in the bilge or near the tank.

NEVER START OR RUN A POWER BOAT IF THERE IS THE ODOR OF FUEL IN THE BILGE ALWAYS HAVE THE VESSEL CHECKED BY A PROFESSIONAL TO LOCATE THE PROBLEM!

  How do I know if the tank is contaminated:

1- The way the engine runs (or doesn't run) will be the first sign of issues it will loose power, and start to run rough. The motor will hesitate and sound like it is miss firing and likely stall. Another sign is hard starting with  a hard time idling, stalling through the shift and popping while running. The motor will also create white smoke out the exhaust. Do not get me wrong there are other issues that can cause these same issues,                          

You have more checking to do to confirm contaminated fuel.

2- If you have a fuel filter in line between the tank and the motor, This filter is a canister and should look like an oil filter. This filter traps water that is leaving the tank on its way to the motor and should be changed in a regular maintenance schedule. To check the condition of the fuel in the filter remove the filter and pour the contents into a clear glass container and allow the fuel to settle for several minutes if the filter is trapping contamination you will see the water sink to the bottom of the glass container (it will look like clear jelly at the bottom). This dump the fuel out of the filter test it is not always accurate as some filters trap water and the only way to know if the filter is contaminated is to change it. 

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3- Remove the fuel line at the filter or fuel pump and draw some fuel from the tank direct and let the fuel settle. Check the bottom of the clear glass container  you are using to inspect fuel samples for water. ( BE SURE THAT YOU DUMP THE FUEL FROM YOUR GLASS CONTAINER AND CLEAN AND DRY BEFORE POURING A NEW SAMPLE TO VIEW) The amount of contamination you find is important to how you remove the water from the tank.

4-No in line fuel filter to dump and inspecting the fuel from the tank is to risky. There is another way to check for water. Take off the flame arrester on the top off the carburetor or throttle body on the top of the motor.(While the motor is not running) Spray some WD40 around the top edges of the carburetor or throttle body. Not a lot just a thin coat and start the motor the spray from the injectors or the mist from the carburetor will contain water and white spots will show up in the WD40. The water will also build up and run down barrel openings of the body.

5- Remove the spark plugs and check the color of the end were the spark takes place. You can read the way a motor is burning fuel by the color on the plugs.

6- If you have experience with fuel you can dip your fingers in the fuel at the carburetor or under the injector spray and see the water it will form little bubbles in the fuel.

   So I have contaminated fuel what can happen to my motor if I continue to operate my boat?

Several issues can and do occur if you run the boat on contaminated fuel:

The first of which is the ignition system will start to fail. Due to the fact that you are trying to ignite fuel that is not wanting to burn properly. The coil wire can burn off, the coil can fail. The cap, rotor, wires and plugs will live a much shorter life. If the ignition side of your boat suddenly fails one of the reasons could be contaminated gas.

The next thing on a carburetor motor is the carburetor itself will act up. The water that does get through the system can corrode the inside parts of the carburetor. This causes flooding and stalling. You may have to rebuild or at the very least service the carburetor. The carburetor can give you issues hours after or years after running on contaminated fuel as the damage on the inside can get worse when the boat is stored or sees a reduction in running hours.

A newer boat with throttle body injection can suffer far more problems. This is a brief list:

Fuel Pump

Injectors

Fuel filter in cooler

Sender failure

Over fuel dumping at injectors

Computer codes

And if you have a hard start even gas in motor oil

Water in Fuel will also eat up spark plugs

The bottom line is contaminated fuel could be and quite often is the culprit of a bad running motor quite often over looked and dismissed as needing a tune up that leads to more and more service. Contaminated fuel can be a costly situation to have to deal with if you only tackle one failure at a time, as they show up. If you have water in the fuel be prepared to go all the way other wise you could have the I AM BACK AT THE DOCK BLUES over and over until the whole system is serviced

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Part 2 will discuss how to get ride of the gremlins contaminated fuel will produce.