Pumparound double check?

[Ted Hamilton]

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

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2014 Praga Dragon / IAME KA-100

[Greg Wright]

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.
Vintage B-Stock Pilot
"When in doubt Gas it, It won't help but it ends the suspense."

[Dale Daugherty]

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/

[Ted Hamilton]

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

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2014 Praga Dragon / IAME KA-100

[Randy McKee]

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

[Tim Salvino]

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.

[Ted Hamilton]

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.

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2014 Praga Dragon / IAME KA-100

[Ted Hamilton]

This should be better:

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2014 Praga Dragon / IAME KA-100

[Tim Salvino]

Perfect!

[Ted Hamilton]

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….

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2014 Praga Dragon / IAME KA-100

[Tim Salvino]

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.

[Alan Sheidler]

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.

[Ted Hamilton]

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!

Swiss Hutless RM80 shifter… Almost ready to fire!!

Posted by Ted Hamilton on Thursday, January 29, 2015

 

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2014 Praga Dragon / IAME KA-100

[Tim Salvino]

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.

[Benn Herr]

You’re welcome!

Shifter Kart Fuel System Primer

[Ted Hamilton]

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

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2014 Praga Dragon / IAME KA-100

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