Pump Jet for the Weber ADF series carburetors.
Includes the o-ring (number 23 in the drawing)
Available from our stock in size:
In order to purchase the correct size, you need to make a choice through the drop down menu just above the "Add to cart" button.
Other sizes may be available on special order.
Please feel free to contact us with your requirements.
Our Contact Page can be found HERE.
The size, or calibration if you want to call it that, is engraved into the jet itself.
That way, you can always determine "what it was when it was produced".
Required quantity per carburettor: 1
This is number 7 and 23 in the drawing.
Weber Part Number: 76407
These jets squirt a pre-determined quantity of fuel down-stream with the air when the accelerator pump is activated.
This is done to prevent fuel-starvation when the throttle is suddenly opened.
Varying the size of the pump jet varies the duration of that squirt:
Larger jet = shorter time
Smaller jet = longer time
For varying the actual quantity of fuel that is "injected" each time that the pump is activated, the stroke of pump itself needs to be adjusted.
These jets are cast from a light alloy.
A calibrated brass bushing, visible in the photograph, is inserted from the bottom.
This, non-removable, calibrated busing is drilled to size and determines the "flow" of the jet.
That size (or flow if you want) is engraved in the horizontal part.
The jet is simply pushed into place and can be removed by hand.