cleaning varnish scum from fuel tank

Discussion in 'Gas Engines' started by scveach, Jun 18, 2006.

  1. scveach
    Joined: Jun 2006
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    Location: Oregon

    scveach New Member

    My 350 chevy is coupled to a 280 volva penta outdrive in a 1981 V2101 Reinell sedan cruiser. Evidently it sat for many years with 1/2 tank of fuel.Previous owner topped off tank with new fuel and it ran great. Now that tank is 1/2 empty it stalls out after running at about 35 mph (5800 rpm), It will restart, idle, and run at 1000 rpm without stalling out but as rpm increases it stalls out. After setting overnight, it will start and run, for about 4 or 5 miles befoe stalling. Any ideas how to clean out extensive varnish buildup in tank that is evidently blocking intake.
    Or any other ideas, other than removing tank from floor mounting.
     
  2. gonzo
    Joined: Aug 2002
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    Location: Milwaukee, WI

    gonzo Senior Member

    Varnish is a hard buildup. It will not clog your fuel system. Install a fuel filter/water separator if there is not one. The symptoms look like the carburetor needs rebuilding. If the fuel stayed in so long it probably clogged it.
     
  3. lee armistead
    Joined: May 2006
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    Location: Ruskin. FL. 33570

    lee armistead Junior Member

    Pressure drain the tank. Procedure: Remove fuel filler cap, plug vent piping, disconnect fuel line before it enters your water seperator filter, add a length of clear vinyl tubing long enough for you to drain the old fuel to a container on the ground. You'll need an air compressor and a nozzle, set compressor pressure to 80 Lbs and start injecting air into the fuel filler port. Try to seal air from escaping back out of the filler port by packing a wet cloth around the head of the nozzle. Let the tank build up pressure and it will eventually force the fuel out of the discharge line into your containers. You will be very surprised at everything that comes out of that tank! Old fuel if exposed to air will get hard, thats why they call it varnish. Fuel remaining in a sealed tank begins a chemical breakdown and starts separating (becomes unblended). The additives will become a consentrate, very thick and collect as a mass in the bottom of the tank along with any condensation accumulation. All will be forced from the tank. Remove the fuel sending unit where the gas guage connects to the tank, use a wet / dry vaccume and insert the suction hose to the bottom of the tank, if the hose is to large adapt one to fit in the opening, vaccume out every thing remaining in the bottom of the tank that would remain below the pick-up pipe. After drained, an automotive supply has a product called "stay dry", an evaporator, add it to the new fuel (5 gallons only) you put back into the tank. You'll have to change the water / fuel seperator filter a couple times. This should help!
     
  4. lee armistead
    Joined: May 2006
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    Location: Ruskin. FL. 33570

    lee armistead Junior Member

    One other thing a warning if you will. If you have an old rusty tank the pressure will show you where your tank is rusted through by producing a nice fuel leak! Should that occur, replace the tank!
     
  5. gonzo
    Joined: Aug 2002
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    Location: Milwaukee, WI

    gonzo Senior Member

    NEVER USE A VACCUUM CLEANER WITH GAS!!! The sparks in the motor will create a bomb.
     
  6. Frosty

    Frosty Previous Member

    Oh the ever cautious Gonzo, Ille bet you use seat belts? But your right, the fumes going through the motor would ignite.

    Incidentaly I once lost a bet about this.

    If you have a tray of gas ( petrol) and you throw into it a lit cigarette --will it ignite the fuel?
     
  7. lee armistead
    Joined: May 2006
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    lee armistead Junior Member

    Gonzo, I beg to differ from you statement. A wet dry vaccume is a sealed unit. Motor is located outside the unit. I guess I should have added "do not use in an enclosed area". Fumes collected on the outside of the container (suction tank) could ignite from motor sparks. I have cleaned out many a fuel tank using the aforementioned procedure to prevent having to remove the tank and shake it out! If there were any possibilities of the general public being harmed from the use of a liquid being sucked to a wet / dry vaccume (water and electricity don't mix either) do you think that underwriter laboratories would give their seal of approval? Think about it! Lee
     
  8. gonzo
    Joined: Aug 2002
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    gonzo Senior Member

    UL gave the approval to the vaccuum used to suck water not flamables. The motor is not sealed, the air exhausts through the motor to cool it down. The float ball is there to prevent the motor to get water in when it reaches the maximum level in the tank. Read the instructions that come with the vaccuum, it says not to use it with flamables.
    Jack Frost: I would appreciate if you stopped your personal attacks. And no, none of my motorcycles has seatbelts.
     
  9. Frosty

    Frosty Previous Member

    Gonzo - personal attack!!! your joking!! -- I was going to agree with you over the vacuum thing but I dont think I will now!!

    For situations such as this when I am apparantly misunderstood by our friends over the pond, I thought it best to print a disclaimer along with all my posts from now on.

    However not detered, I was more taken back with your last comment,--- your a biker?
     
  10. Willallison
    Joined: Oct 2001
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    Willallison Senior Member

    Oh Gonzo - don't worry about Jack - he's a grumpy old bugger, but means no harm;)
    And you are indeed correct. The only type of electrical equipment that should be used around anything flammable are those that are classed as "Intrinsically Safe". The fact that people get away with using equipment that they think is ok, doesn't mean that their not taking their lives into their own hands each time they do it...
    Sorry Lee - no aspersions on your character intended!
    The only time I would work on a fuel tank - and that includes cleaning it - is after it has been checked and classified as "gas free", by someone with the correct epuipment for doing so. Fortunately, it's one of the things I do for a living, but it won't cost you an arm and a leg. Not getting it checked may do just that and more - literally.
     
  11. drewpster
    Joined: May 2006
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    Location: Chattanooga Tn

    drewpster Unlubberly

    The only way I know to do this job correctly includes removing the tank. (Sorry) The thing about tanks is, there is no way of knowing how bad the contamination is. Years of build up from all sources can continue to be a problem after the whole fuel system has been renewed, even if the tank has been cleaned out. It very difficult to remove varnish easily. Any varnish left in the tank is likely going to come loose at some point and clog the system again. Evedince of this can be seen as small brown flecks in the filters. I have heard, and tried, many different methods of cleaning out tanks. It has always been a gamble. The only method I have found that works every time is to drain the tank, remove it, flush it with salt water, FILL IT WITH WATER COMPLETELY, and use a pneumatic die grinder to cut it in half. Then use cleaners to clean it out and make whatever repairs it may need. Then tig weld it back together. Obviously we are set up to do this kind of work and I do not recommend a novice try it. If you want to have a professional shop do it consider the cost. Unless you have a large tank it may be more cost effective to buy a new tank. (250 gal is our minimum)

    Safety Note! Before anyone jumps on me let me be clear. There are accepted, tested safe, methods to cut, weld, and do all manner of work on fuel and chemical tanks. If you do not know, and are not practiced in these methods, Don't try it!
     
  12. gonzo
    Joined: Aug 2002
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    gonzo Senior Member

    I use an electric fuel pump to drain tanks. It is sealed so there are no sparks.
    Jack Frost: no offense intended. Let's make peace. Yes I am a biker.
     
  13. Frosty

    Frosty Previous Member

    Gonzo --always at peace,-- my natural state. This is not the thread but my apologies to the thread starter. Milwakee,-- is that where they make Harleys.

    Again wrong place but I would love to hear more. I assume you have a Harley,--- or two? Orange county Choppers is one of my favourite programs on National geographic. I have an intruder 1400 ( yeah yeah a metric).

    Yes right a diaphrgam type fuel pump with the pipe taped tight to a wooden stick. You can then get into most corners through an inspection hatch. If not you have to take the tank out and put in some water and detergent and chippings ( yes chippings of the road) Hard gravel or nuts and bolts then give it a real hard swirling and shaking. This is very hard work but will clean the tank. Like cleaning a cement mixer with stones??

    Put the tank out in the sun to dry. I have done this many times on cars, boats and----bikes!!
     
  14. gonzo
    Joined: Aug 2002
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    gonzo Senior Member

    I have cleaned small tanks with gravel. It would be difficult with a large one. The new "reformulated fuels" in USA have methanol which disolves old deposits. It is good to keep new or clean tanks clean. However, it will clog a fuel system if the tank was too dirty. Varnish is hard, and if you leave it alone it won't harm anything.
     

  15. l_boyle
    Joined: Sep 2006
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    Location: United States

    l_boyle ol' can of sardines

    It sounded like a dirty carburetor to me. After overnight sitting the dirt and gunk settled to the bottom of fuel bowl, when you start it up and run the hell out of it, the dirt get stirred up and clog the jettng and ports in the carburetor. Before you yank that tank out, try putting carburetor repair kits in first. My truck acted the same way, till I repaired the carb, I was surprised with my results, after putting in all day long job pulling fuel pumps, yanking the tank, wasted about 25 gallons of fresh gas, buying new hoses and clamps, a lots of heated words said...
     
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