Fuel Tank Contamination (for your information)

[Seemann]

Sorry, new member. Don't know exactly where to put this thread. Moderators, please feel free to move it where it belongs. Since it is not engine specific I though nit might fit here. I have an 1997 Hurricane Fundeck 196 configured for fishing. It has a Mercury Mariner 125 hp 2 cycle outboard engine, probably 1989 or 1990. I bought this rig in 2018 and I am still making repairs. The first problem I encountered was hard starting, rough idling, and stalling when shifting gears. It got to the point that it wouldn't start. The problem was a contaminated onboard fuel tank. Apparently there was abrasive metal particles, and non metallic particles mixed with the gas in the tank. These particles actually cut through the gas filter/watertrap, and engine mounted gas line filter, and deposited in the four carburetor fuel bowls blocking the needle valves. A thorough cleaning of the carbs, and replacement of the filters resolved the problem.
I am no longer using the onboard fuel tank because it would be a nightmare to clean, and almost impossible to replace. This presents another problem, however. I purchased two portable 6 gallon plastic fuel tanks at Walmart, and a new supply hose. The Attwood hose connection did not fit properly so I replaced it with the original Mercury hose end. I ran the engine successfully until the end of last season. After a few weeks I tried to start the engine, but it quit after a few seconds. I tried repeatedly to start the engine without success, and eventually caused blue, then dense white smoke to appear in the exhaust. I was obviously injecting oil into the crankcase, but no gas. Maybe there was some condensation as well.
The cap vent on my portable tank was open, however, my tank was obviously bulged by the warm temperature and sun. I believe pressure in the tank forced fuel into the engine fuel line and fuel pump causing the pump diaphragms to expand, or rupture, thus not delivering fuel to the engine. The engine is currently being repaired so I can't give you the answer to this problem, but I will at a later date.
I hope that these experiences will be of some help to those of you with older engines, and portable tanks. I suggest disconnecting the gas supply hose to prevent the possibility of fuel pump damage. I still need to find out why my portable tanks are not venting properly.

 

[dingbat]

Sorry, new member. Don't know exactly where to put this thread. Moderators, please feel free to move it where it belongs. Since it is not engine specific I though nit might fit here. I have an 1997 Hurricane Fundeck 196 configured for fishing. It has a Mercury Mariner 125 hp 2 cycle outboard engine, probably 1989 or 1990. I bought this rig in 2018 and I am still making repairs. The first problem I encountered was hard starting, rough idling, and stalling when shifting gears. It got to the point that it wouldn't start. The problem was a contaminated onboard fuel tank. Apparently there was abrasive metal particles, and non metallic particles mixed with the gas in the tank. These particles actually cut through the gas filter/watertrap, and engine mounted gas line filter, and deposited in the four carburetor fuel bowls blocking the needle valves.

This isn’t a “heads” up as much as a case study in what not to do.

The Atwood fuel line has a know issue with the inner hose liner disintegrating over time. I would put good money that the non metal prices you found in the fuel pump came from the hose

Outboard manufacturers specify the use of 10 micron fuel filter. Yet most people use filters (20 micron or better) designed to keep sticks and stones out or nothing at all.

To make matters worst, people dump the fuel filter and reuse them…would you drain and reuse a oil filter?

A good quality 10 micron filter is a must to prevent such things. I highly recommend Racor, water separators with the clear bottom that allow you to see and drain any condensation that accumulates before it becomes a problem. Having said that, the filter still needs to be changed on a regular basis.I change mine as part of annual PM

As far as your main tank is concerned, E10 is the best fuel system cleaner on the market. Fill the tank with grease fuel. Install a good quality 10 micron filter, keeps a spare on hand, and go boating.

 

[Seemann]

This isn’t a “heads” up as much as a case study in what not to do.

The Atwood fuel line has a know issue with the inner hose liner disintegrating over time. I would put good money that the non metal prices you found in the fuel pump came from the hose

Outboard manufacturers specify the use of 10 micron fuel filter. Yet most people use filters (20 micron or better) designed to keep sticks and stones out or nothing at all.

To make matters worst, people dump the fuel filter and reuse them…would you drain and reuse a oil filter?

A good quality 10 micron filter is a must to prevent such things. I highly recommend Racor, water separators with the clear bottom that allow you to see and drain any condensation that accumulates before it becomes a problem. Having said that, the filter still needs to be changed on a regular basis.I change mine as part of annual PM

As far as your main tank is concerned, E10 is the best fuel system cleaner on the market. Fill the tank with grease fuel. Install a good quality 10 micron filter, keeps a spare on hand, and go boating.

Thanks for the heads-up on the Attwater fuel line. It wasn't installed at the time I had an issue with fuel contamination. I purchased it with the two 6 gallon portable tanks. I now have the Attwood fuel line connected to a large fuel filter/water trap. From there I added 6 feet of 5/16" fuel hose from Advance Auto to the engine fuel port. I also replaced the engine inline fuel filter again just in case. What do you mean by "grease fuel"? I've been adding "Sea Foam" additive to the no ethanol gas as well.

 

[Chris1956]

Contaminated fuel is not the end all. If the fuel level gauge is accessible, remove it and tilt the trailer tongue all the way up. This puts the fuel in the rear part of the fuel tank. Now siphon it all out and either filter it or dispose of it.

 

[dingbat]

What do you mean by "grease fuel"?

Spell check strikes again....should have been "fresh" fuel.

 

[Texasmark]

This isn’t a “heads” up as much as a case study in what not to do.

The Atwood fuel line has a know issue with the inner hose liner disintegrating over time. I would put good money that the non metal prices you found in the fuel pump came from the hose

Outboard manufacturers specify the use of 10 micron fuel filter. Yet most people use filters (20 micron or better) designed to keep sticks and stones out or nothing at all.

To make matters worst, people dump the fuel filter and reuse them…would you drain and reuse a oil filter?

A good quality 10 micron filter is a must to prevent such things. I highly recommend Racor, water separators with the clear bottom that allow you to see and drain any condensation that accumulates before it becomes a problem. Having said that, the filter still needs to be changed on a regular basis.I change mine as part of annual PM

As far as your main tank is concerned, E10 is the best fuel system cleaner on the market. Fill the tank with grease fuel. Install a good quality 10 micron filter, keeps a spare on hand, and go boating.

On the fuel line internal liner disintegrating, I experienced that on two boats after about 10 years of age. Shows up as brown chips and semicircle particles in the fuel filter. The new grey hose kits, with the "oval" bulb, costing $35+ for the bulb mounted in 3' of hose have all this spec writing on the side, yet are still grey silicon looking/feeling like the old hoses...wonder if anything changed?

 

[dingbat]

On the fuel line internal liner disintegrating, I experienced that on two boats after about 10 years of age. Shows up as brown chips and semicircle particles in the fuel filter. The new grey hose kits, with the "oval" bulb, costing $35+ for the bulb mounted in 3' of hose have all this spec writing on the side, yet are still grey silicon looking/feeling like the old hoses...wonder if anything changed?

Do they still sell it at Walmart?……lol
I use Trident A1 barrier hose from the filter to the pump.

Always use OE bulbs

Trident Trident Barrier Lined A1-15 Fuel Hose - #365 -

Trident Barrier Lined A1-15 Fuel Hose for both gasoline (including ethanol blends) and diesel (including bio diesel blends). Read More →

tridentmarine.com

 

[Seemann]

I just got my boat/engine back yesterday. According to the mechanic trash, and grit from the fuel caused two needle valves to remain open allowing too much gas (like full choke all the time). In addition, there was rust inside the carburetors that caused another needle valve to fail. I speculated on water in the tank due to condensation, and I was correct. I purchase my unleaded/no ethanol gas from two service stations. I never saw any contamination in the fuel, but I guess I'll have to pre-filter my fuel before transferring gas from my "Fill" tanks to my portable 6 gallon tanks that are connected to my engine.
My speculation about the fuel pump being damaged was incorrect. The pressure is fine, although the mechanic did note that my portable tank caps did not vent properly. I have two "Neptune" 6 gallon plastic tanks that I purchased in Walmart. I intend to email the manufacturer to find out how to remedy the venting process.
When I abandoned my contaminated onboard gas tank, and switched to the portable tanks I purchased an Attwood hose kit for the Mariner engine at Walmarts. Recently, I had a discussion with a charter boat captain about my starting problems, and he stated that he heard that Attwood fuel lines tend to deteriorate after use. I cannot verify that statement, nor do I wish to malign the Attwood company that has many fine products out there, but I would really like to know if there is any substance to that statement. As a precaution I am going to discontinue the use of that hose, substituting 5/16" gas line hose from Advance Auto, and connect the siphon bulb in between.
This is my second experience with fuel contamination, and I hope to prevent it from happening again. I use Sea Foam with every tank, yet I had some gummy residue in the carbs. I'll try adding Stabil to my "Fill" tanks to avoid sour fuel. I will be adding a fuel filter/water trap in my new fuel line as well. I would appreciate any suggestions.

 

[Chris1956]

Find a better gasoline source. Fuel from gas stations should be clean and fresh. it sounds like you are getting old dirty gasoline.

Rust in the carbs did not come from the carbs nor likely from the boat fuel tank. That points to the gas station

I would recommend a fuel/water separator. You should not need to use Seafoam or other additive, if you have one.

I also recommend unleaded fuel with alcohol. The alcohol absorbs water and keeps the fuel system clean.

If you suck the onboard fuel tank dry, and refill with filtered or fresh gasoline, it should be fine.

 

[Seemann]

Thank you Chris for your response. I am installing a new gas filter/water separator between my portable tank and the engine. I've been using only unleaded/no ethanol fuel since I bought the boat. It was recommended because alcohol destroys rubber seals and membranes. I only have two local sources for that fuel so I will pre-filter it before putting it in my tank. The Sea Foam helps to keep the carbs clean, and free from gumming. I did have water present in my fuel from condensation, and it did rust some of the ferrous metals in the carb, but in only one. If the rust was present in the gas I would have expected to find it in all four carbs. I'm thinking of adding an inline fuel filter between the water separator and engine, similar to the one on the engine, to see if any debris is getting past the water separator. They are plastic and can easily be cut open to examine the filter material at the end of the season.
I still have 15 gallons of unleaded/no ethanol gas sloshing around in my onboard tank. I plan to pump it out, filter it, and use it in my farm tractor. I may continue to do that until my filter is free of debris.

 

[Chris1956]

Your motor (if a 1997 or newer) is made for unleaded alcohol fuel. The membranes and fuel lines will last just fine.

A water separator is all the filtration you will need. it separates water by gravity, and contains a 10 or 20 micron paper filter which is more than adequate. Debris will not get thru it. More filtration can restrict fuel flow to the carbs which can damage your engine.

I have never seen a carb with ferrous metal parts. They are aluminum bodies, brass jets and stainless steel screws and hardware. Not sure what you have.

If you want to use Seafoam at .50/gallon to protect against a non-problem, that is your choice. The alcohol in gasoline will absorb any condensation normally present.

OK third time is the charm, I hope. Suck the fuel out of your onboard tank and filter or discard it. Any water will settle to the bottom of the container and can be poured off. Fill the onboard tank with fresh gasohol and go boating.

 

[mike_i]

Exactly what he said ^^^^

 

[Seemann]

I'd be very happy to use unleaded regular. The no ethanol gas is a lot more expensive. My boat registration lists my boat as a 1997 FB196OB, it doesn't specify a date for the engine which could be the same age, older or newer. I bought the boat used so I don't have a history to fall back on. My 125 hp Mariner serial number is OG360059. I've used it to get a manual, order parts, but never got a date of manufacture. Obviously my filters are not good enough to stop trash, grit and rust from getting into my carbs. My fuel pump pressure tested good so I'm considering adding a second gas filter/water trap in series with the one I have. I'll get one that has a drain on the bottom.

 

[mike_i]

Get a 10 micron filter

 

[Seemann]

My Attwood gas filter/water trap is 10 micron. I contacted Mercury/Mariner by email and inquired about my engine. The following day I was contacted by Jerry from MercMarine Customer Service who was nice enough to answer my question. My engine is a 1996 2 stroke 125hp Mariner outboard. The recommended fuel for this engine is regular unleaded/no ethanol gas. He further stated that I can use regular/unleaded with up to, but no more than 10% alcohol IF I use a gasoline stabilizer such as Stabil with it. I will continue using regular unleaded/no ethanol gasoline, but I will take extra precautions to ensure that it is clean. Hopefully that will resolve my bi-annual starting problem. Thanks for all your comments, I have taken all into consideration and appreciate y'all taking the time to help me out.

 

[Chris1956]

Jerry has covered his butt with that answer. Gasohol E10 has been used in much older motors than yours, w/o incident.

 

[Seemann]

I'm back on the water, and my engine is running fine. I'm still hooked up to my portable tanks since I have not yet polished the fuel in my onboard tank, or pumped it out. I'm looking for a decent 12 volt gasoline transfer pump for that purpose. As far as my Neptune portable 6 gallon tanks go, Neptune states that "bulging" is normal. Apparently the EPA required them to provide a tank cap that would not vent out until internal pressure reaches 5 psi. The purpose is to retain expanded fuel vapor inside the tank to hopefully condense rather than escape into the atmosphere. The cap would function normally to allow air in when fuel is being used by the engine. I feel better now.