Home Forums Shifter Karts Pumparound double check?

This topic contains 15 replies, has 7 voices, and was last updated by  Ted Hamilton 2 years, 9 months ago.

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  • #41171

    Ted Hamilton
    Participant

    Just wanted to make sure my pumparound is right…

    From the fuel tank pickup, the line goes to the fuel pump “IN”.  Then a single line comes from the fuel pump “OUT” to a Y.  The unrestricted line (shorty) goes to the carb.  The other side of the Y has the top of a spark plug twist-on in it to act as a restrictor, then goes back to a 2nd vent nipple on the fuel tank… Sound right?  Pic below… Thanks!   ~Ted

    www.facebook.com/hamiltonhelmets/
    2014 Praga Dragon / IAME KA-100

    #41182

    Greg Wright
    Participant

    Uhhhhh Ted, That’s not a pump around system. Should work just fine though, I’ve never needed a restrictor in the return line but many use them.

    Greg Wright
    Rapid Racing Inc.

    "When in doubt Gas it, It won't help but it ends the suspense."

    #41185

    Dale Daugherty
    Participant

    Here is a good pump-around diagram:

    http://www.swedetechracing.com/news-events-blog/wp-content/uploads/2010/03/PumpAround-diagram.jpg

    Mine was built by SRS and is a bit different. There is a “Y” split after the “Out” from the supply pump. One branch goes to the carb “in”, and the other goes back to the tank with a restrictor (unsure of restrictor size). Then there is of course the return line from the carb that goes through the return pump and then to the tank.

    2010 Spirit [Birel] SP32 // SRS CR125 - Stock Honda [#08]
    Hill Country Kart Club - New Braunfels, Texas - http://daledaugherty.wordpress.com/

    #41188

    Ted Hamilton
    Participant

    Thanks for the correction on the terminology, glad it will work.  Thanks!  So, what is my type of system called? 🙂

    www.facebook.com/hamiltonhelmets/
    2014 Praga Dragon / IAME KA-100

    #41191

    Randy McKee
    Participant

    Your’s is a single pump fuel system.  As Greg said, it should be fine.

    A pump-around system uses 2 pumps and a modified carb to work with 2 pumps. 1 pump is for feeding carb and the other to scavenge the excess and send it back to the tank.

    Here’s a pic:

    http://www.fastech-racing.com/pump-around-modification.html

    #41291

    Tim Salvino
    Participant

    Ted, everything looks good, up until the “T”

     

    The inlet is fine. Switch the two outlets. Put the carb outlet line on the barb facing down. Put the tank return line on the horizontal barb. Remove the restrictor in the tank return line. Make the carb feed line shorter so it is a straight, verticle tube, with minimal bends.

     

    This will give you as close to a gravity feed setup as possible. Seeing as that carb (and all ‘moto’ carbs) are designed for a gravity feed setup, they are VERY picky about getting too much fuel pressure.

     

    I will take a picture of my setup so you can get a better idea of the fuel line orientation. It has worked great so far with no starvation or flooding issues.

    #41302

    Ted Hamilton
    Participant

    I have a “straight tee”, so I’ll put that on there with the base of the T down to the carby and the pump send and tank return on the top arms…  Thanks for the tip.

    www.facebook.com/hamiltonhelmets/
    2014 Praga Dragon / IAME KA-100

    #41303

    Ted Hamilton
    Participant

    This should be better:

    www.facebook.com/hamiltonhelmets/
    2014 Praga Dragon / IAME KA-100

    #41306

    Tim Salvino
    Participant

    Perfect!

    #41308

    Ted Hamilton
    Participant

    Thanks for the tip…. Now I just hope that the carb isn’t all gummed up and that she fires right up.  I wonder if a Honda 80 RCE pipe will fit this ‘Zuki….

    www.facebook.com/hamiltonhelmets/
    2014 Praga Dragon / IAME KA-100

    #41310

    Tim Salvino
    Participant

    You know you would be better off cleaning the carb now, rather than later… lol

     

    Save yourself the headache! You are going to have to do it anyway.

     

    Oh, and I always find a nice shot of starter fluid down the carb throat really makes the starting procedure a lot quicker. No need to prime the entire fuel system.

    #41363

    Alan Sheidler
    Participant

    Well OK, Tim….

    But you really should not use starting fluid in a 2-stroke motor.  You have to remember that the intake charge goes through the crank-case.  Anything other than fuel and the appropriate oil going in there can have a detrimental effect on bearings.  The stuff can be corrosive, and it is volatile, of course.  Unlikely, but still possible that it could ignite under the piston, instead of on top of it.

    #41377

    Ted Hamilton
    Participant

    I wasn’t going to use starting fluid because of the lack of lube, but I was also going to dump some marvel mystery oil / gasoline through the plug hole before I fired it too, so it wasn’t a “dry” spinover to start.

    I’m looking forward to my first road course shifter kart….I played with a 60cc on a 1/10 asphalt oval once… this will be better!

    https://www.facebook.com/video.php?v=10100663144070809

     

    www.facebook.com/hamiltonhelmets/
    2014 Praga Dragon / IAME KA-100

    #41383

    Tim Salvino
    Participant

    2-3 seconds at less than 3k rpm is NOT going to hurt anything. And most off the shelf starting fluids have lubricants mixed in.

    #41507

    Benn Herr
    Participant
    #41515

    Ted Hamilton
    Participant

    Good info, Benn…. think I will stick with my Tee system, and add restrictor if I’m seeing starvation issues.

    www.facebook.com/hamiltonhelmets/
    2014 Praga Dragon / IAME KA-100

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