18 hp with a pressurized tank

Discussion in 'Bubba's Outboards' started by 1sporticus, May 20, 2007.

  1. 1sporticus

    1sporticus Active Member

    Messages:
    1,006
    State:
    Iowa
    Hi Guys, I have an old 18 hp evinrude, that takes the pressurized tank, is there any other way to run this motor with some mods or possibly an electric fuel pump? Hope you can help. Later Andy
     
  2. Bobpaul

    Bobpaul New Member

    Messages:
    3,039
    State:
    Supply NC
    I've never done it, but I've been told that the pressure/pulse line from the crank case that pressurizes the tank can also be aplied to a mechanical/pulse fuel pump.

    You'll need a fuel pump with three fittings though. An inlet, outlet and the pulse line. The more common ones mount to the crank case over the pulse hole.

    I would think an electric one would also work, and be cheaper.
     

  3. Catwagon

    Catwagon New Member

    Messages:
    125
    State:
    Justin, TX
    OMC used to make a kit that contained a new drilled upper bypass cover and a "modern" fuel pump plus the gas hose to reroute fuel. It also gave instructions to plug the positive pressure pulses that originate from the valve located in the intake manifold under the carb.
    That kit is no longer availible, but if you can locate an early '60's upper bypass cover from a used parts yard plus the matching fuel pump you can copy it. Just pinch off and solder the port that supplies pressure pulse to the tank and mount the newer upper bypass cover and pump.
    Finally get a newer style single line fuel fitting and replace your twin fuel fitting at the base of the powerhead with it. Hook your fuel hoses up and then you've pretty much duplicated the old kit. Next, go buy yourself a new plastic tank and then put the old one plus all the hoses and fittings on eBay where they will usually sell for a very nice price.

    I've done this myself on several motors and it works nicely.
    (note, some of the smaller johnyrude motors don't have bypass plates and you have to use an aftermarket Mikuni fuel pump and change what you do with the impulse port, which is a pain in the butt if you don't know exactly what you're doing.)
     
  4. Catwagon

    Catwagon New Member

    Messages:
    125
    State:
    Justin, TX
    I ran out of time trying to re-edit the above post to note that the manifold should first be removed from the engine before flame soldering this port. Obviously gas burns very well and this port leads directly into the crankcase. Should you iginite the gas fumes the whole crankcase may explode resulting in injury or death.

    Completely remove the manifold from the engine if you're going to flame solder this port.

    The best and easiest (no manifold removal needed) option is to mechanically plug the port with a short length of vaccum hose and some kind of tiny plug for the remaining hole.
     
  5. Bobpaul

    Bobpaul New Member

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    Now that's the type of input that belongs on an informative forum. Not the chatroom bs that can go on and on till the question and answer gets lost.

    Thank you, Catwagon.
     
  6. Bubbakat

    Bubbakat New Member

    Messages:
    4,532
    State:
    McMinnvill
    Bob I liked his response so much I even gave him some rep points.:cool2:
     
  7. PeZ

    PeZ New Member

    Messages:
    757
    State:
    Oklahoma
    LOL any sentence ending with injury or death needs to be quoted lmao.
     
  8. Catwagon

    Catwagon New Member

    Messages:
    125
    State:
    Justin, TX
    Gosh guys, thanks very much.

    There's not alot of things I know about so it's hard to make a solid contribution on the BOC the majority of the time. I'm truly glad to hear it was a useful post to you.
    Thank you very much for the rep points and the "thank you" notes, you all made my day. =)

    I just wanted to make sure that no one here accidentally nominated themselves for this years' Darwin awards, :lol:
     
  9. 1sporticus

    1sporticus Active Member

    Messages:
    1,006
    State:
    Iowa
    I haven't actually taken time to study this engine much, but one of my thoughts was is it possible to adapt a fuel pump from say a Kohler or briggs engine. They have a 3 fitting setup, one for vacuum, and a in and out.
     
  10. 1sporticus

    1sporticus Active Member

    Messages:
    1,006
    State:
    Iowa
    Hey Catwagon, do you have any literature on this setup?