Pump around system pumps MUST BE CLEANED EVERY RACE WEEKEND.  THIS IS NORMAL MAINTENANCE JUST AS ADDING AIR TO TIRES, FUEL TO THE KART OR LUBRICATING THE CHAIN.  DO NOT SKIP THIS STEP.

First things first - Make sure that all of your fuel line fittings have a minimum I.D. of 3/16″ diameter.  This includes fuel tank nipples, vent nipples, fuel filters, and catch can nipples.  This does not include the vents on the carburetor itself.  Make sure all fittings are properly secured and safety wire or clamped at each fitting.  Air can leak into the system at these connections and cause a problem.  For the vent catch tank, make sure the tank is drilled out with at least a 1/4″ diameter vent hole.  If the catch cannot breath, the system will not work.  When checking all the I.D. sizes, make sure the nipples are clear of any obstruction.

Make sure all of your fuel lines are routed properly to each fitting.  Do not assume it is right, Check it.  The pump around system that SwedeTech supplies use the Mikuni Round style pumps.  These pumps have arrows on the cover to indicate fuel flow.  Double check that the fuel is flowing in the right directions.  If the arrow is pointing to the center of the pump, this is the inlet.  If the arrow is pointing away from the center, this is the outlet.  On the pump around pumps, one outlet on each pump is plugged with a set screw.

The pickup line in the fuel tank should reach the bottom of the tank and lay flat on the bottom.  The end of this hose should have a brass nozzle that lies on the bottom of the tank.  Make sure that the fuel line cannot be pinched or pressed between chassis parts, seat parts, weights, etc.  Any restrictions in flow will affect performance.  Make sure when you secure fuel lines to the frame, that you DO NOT over tighten the fuel line.  This will restrict flow.  Note the common theme, DO NOT RESTRICT FLOW.

Start with the routing of the fuel line.  Connect the fuel “supply” line to the tank nipple that has the fuel pick up tube inside the tank.  Between this line, and before the supply pump, add a fuel filter.  The “supply” line will connect to the fuel pump half that you designate as supply.  Both pumps work the same, as long as the fuel follows the arrows.  Connect the line to a pump with an arrow pointing to the center of the pump.  It may help to label one pump “supply” and one pump “return”.   Take another length of hose from this pump half and route to the carburetor inlet.  Typically this is a brass inlet, with some being supplied with an aluminum nipple pressed into the end.  It will also be a barbed fitting.  This arrow should be pointing away from the center.  Leave enough fuel line so you can remove the carburetor easily for jet changes.  Make sure the lines CANNOT get pinched or restricted.  Secure all supply connections.

The carburetors that SwedeTech supplies for the pump around all have the fuel inlet or “supply” on the left side of the carburetor. The return tube is always on the right side of the carburetor. Left side is determined by the view if you are sitting in the kart looking forward.

Now for the fuel “return” line.  The tank will have at least two available nipples.  Designate one for the vent line and one for the return.  (The supply line is complete).  From the tank to the other fuel pump half, connect fuel line to the pump with the arrow pointing away from the center.  This is the return side.  Note the direction of arrows and the fuel flow.  Now connect another line to the other available fuel pump nipple with the arrow pointing to the center.  Connect this piece of fuel line to the carburetor return tube (typically you can tell this was an added tube, and usually it is parallel to the carburetor slide body.  It is also a straight tube with no barb).  Make sure you have enough fuel line to easily remove carburetor for tuning.  Secure all connections.

The final nipple available on the fuel tank should be your vent tube.  Some tanks have 4 nipples, plug the 4th.  Check with your local rules.  Some associations require a catch tank on the vent.  Make sure the catch can is drilled out on the inlet with a minimum of 3/16″ I.D. and the vent hole in the catch can is a minimum of 1/4 I.D.

Diagram compliments of Benn Hur

The above steps are the basics to routing a pump around properly.  If you do not follow the above procedures, you may have problems.   Below is a checklist of common problems.

• Fuel is spraying out of the vent line of the tank
  • System is pressurizing, fuel is being sucked out of the tank when it tries to achieve equilibrium.
  • Check guide above to make sure your system is plumbed properly
  • Check the fuel pumps for buildup of oil or failed fuel pump half

• Fuel is spraying out of the vent lines on the carburetor
  • System is not properly returning fuel to the tank
  • Check guide above to make sure your system is plumbed properly
  • Check the fuel pumps for buildup of oil or failed fuel pump half
    • This is typical if the “return” fuel pump is not working properly
  • Make sure all fuel lines are not pinched on the return to the tank

• Carburetor has a bogging or flooded sound
  • Check pumps for oil build up or failed pump half
  • Double check your plumbing with the above guide

By following the above guidelines, you will eliminate most of your pump around problems.  These systems are sensitive and need to be maintained properly.

I hope this information helps.

To order replacement parts, visit the links below

Fuel pump rebuild kit – requires 2 per system

Fuel pump kit – keep one clean at all times

Fuel Line – typical system uses 10′ – 12′

Fuel Filter – always run a filter

Fuel Pump Mount – rubber isolated

Pulse Line for pump – cloth braided