Petrol pipes

Discussion in 'Outboards' started by valvebounce, Jun 27, 2016.

  1. valvebounce
    Joined: Dec 2010
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    Location: manchester uk

    valvebounce Senior Member

    I have replaced all my petrol lines on my 1964 18hp Evinrude.
    The engine runs very well.
    The pipes have been on for about 3 months.
    I have noticed tiny white strands in the glass filter bowl.They swirl around
    when the bulb is pumped.
    I have replaced the fuel with new,and the 2 stroke oil is of a good quality.
    I cleaned the tank,and flushed the fuel through,and removed the drain plug
    out of the carb bowl,emptied it and replaced the bolt.
    The pipes I bought were diesel and petrol proof and modern materials.
    Is it possible that the Ethanol in the petrol is causing the pipes to deteriorate?
    The fuel is 100 Octane,and I have tuned the engine to run on it.
    Normally,when I follow this procedure,I have no problems.
    Anybody had a similar problem?
     
  2. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    Is any part of the system remaining from the old stuff, such as the bulb?
     
  3. powerabout
    Joined: Nov 2007
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    powerabout Senior Member

    you dont use telflon tape anywhere do you?
     
  4. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    No, Teflon is infamous for clogging things up. I've pulled strings and shreds of this stuff out of many fuel systems. Never use an RTV either.

    [​IMG]

    This is the stuff to use.
     
  5. powerabout
    Joined: Nov 2007
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    powerabout Senior Member

    I like loctite pipe sealant for hose barbs but do use that stuff as well
     
  6. valvebounce
    Joined: Dec 2010
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    valvebounce Senior Member

    Hi PAR,
    all the pipes and the bulb are new.I haven't needed to refit a gasket anywhere on the system.
    I have definitely not used PTFE tape..
    The pipes I have used have the BS stamp all over them(british standards)
    They are for road vehicles,but flexible enough for an outboard.
    The whole system is sound(no leaks)
    The strands are very short and thin,(just noticeable)
    they resemble f/glass strands.
    I can only suspect a material degeneration fault.
    I have fitted quick change racing bike connectors so I can change tanks without any messing about.Also change from the Evinrude to the Yamaha auxiliary engine.The connectors cut off when disconnected,and are good quality.There are no materials in them to degenerate.
     
  7. valvebounce
    Joined: Dec 2010
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    Location: manchester uk

    valvebounce Senior Member

    Hi PB,thanks for your interest,
    I've replied to PAR with some details.
     
  8. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    If it looks like monkeyshit, it probably is monkeyshit (what's it smell like ;)). Can you get a better look with a magnifying glass or even a microscope? What's the tank made out of?
     
  9. valvebounce
    Joined: Dec 2010
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    valvebounce Senior Member

    On thinking about it,the first point of being able to detect the strands is the glass bowl,
    Which is before the petrol pump and just after the engine fuel connector.
    I know the main engine connector is in good condition because I replaced it.
    So the strands are originating between the tank and the glass bowl.
     
  10. valvebounce
    Joined: Dec 2010
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    Location: manchester uk

    valvebounce Senior Member

    The strands are white and don't collapse when rubbed between your fingers.
    The tank is a red nylon Quicksilver tank.
    The pickup pipe in the tank has a tube filter on it
     
  11. SukiSolo
    Joined: Dec 2012
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    Location: Hampshire UK

    SukiSolo Senior Member

    I'd guess your garage/fuel supply is the problem. Certainly run into water in bought petrol from garages......;) At least if you decant some of the 'new' fuel into a jar it should settle and show any contamination - water sits under petrol but only 2 major (and cheap) polymer groups float without a foaming agent.

    Did you solve this problem?
     
  12. valvebounce
    Joined: Dec 2010
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    valvebounce Senior Member

    Hi SS,
    I think I have sorted it out.
    The tank pickup pipe filter was perished,which is unusual in most cicumstances.
    The tank was pretty low on fuel and a bit exposed to the elements.what I thought was the position of fully tightened down on the air bleed in the cap wasn't.The bleed screw had stiffened up in a position not quite shut off.I know I had left it in what I thought was a fully tightened down position.I tried it with a pair of nose pliers,and it went down another 2 turns.
    I suspect that with the change of temperature and expansion and contraction the water got sucked in.(Warm day,rain,change in temperature of the tank)
    I think the water got frozen in the tank and damaged the fibres in the filter on the pickup pipe,and the tiny white specks are actually the damaged fibres off the filter.
    I think if the tank had been in regular use the air bleed would have been lubed by the splash of petrol and oil,and not of stiffened up.
    Lesson learned,I'll be throwing any old fuel away that's been stood a while and checking the bleed screw travel.
    Haha,just call me Sherlock.
    "V"
    Hopefully this info will be of use to the boating fraternity.
     
  13. SukiSolo
    Joined: Dec 2012
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    Location: Hampshire UK

    SukiSolo Senior Member

    Thanks for the update. One other thing, worth checking though often ignored, is the breather actually works! Just releasing the upper screw/vent does not mean the vent itself is clear. I've known it on a couple of occassions. Remove it and just blow through the cap, if you can't, well put an air line or a bit of thin strimmer line through....

    Often you can mix a bit of old fuel with new and it works fine. Only really old stuff 2 years or more starts to give real problems in my experience of UK fuel. When it comes to mixture screws and passageways in carbs though, a couple of months can give problems on the really finicky ones....
     

  14. valvebounce
    Joined: Dec 2010
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    Location: manchester uk

    valvebounce Senior Member

    I washed the cap through with actone and blew it through.
    I unplug the fuel line and let the motor run out of fuel,it seems to prevent the oil residue building in the carb etc.
    I know from my bit of motocross experience,fuel loses it potential pretty quickly.
    Although I don't think it's so critical in outboards.
    One thing I do,is if the fuel is in doubt,get rid of it. It can cost more in the long run.
    Thanks for your reply
     
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