Note: These instructions are for reference only and may differ
with each engine. Before making any adjustments, jot down on
a piece of paper your original adjustments just incase you need
to refer back to them later. Remember a rich condition is always
better then a lean one. Running your engine to lean may cause
series damage to your engine.
How do I adjust the jets on my High-Performance Carburetor?
First of all, locate the "L" and "H" markings on the carb case.
These markings are located next to their corresponding "Low" and "High" speed needle valves.
Step 1: Set the low-speed (small, slot-head screw located next to the "L" on the carb body) jet to 1 1/2 turns out.
Step 2: Screw the idle speed screw all the way in.
Step 3: Set the high-speed (T-handle screw located next to the "H" on the carb body) jet 3/4 turn out.
Step 4: Start the engine (you may need to adjust the low-speed screw slightly in one direction or the other to get the
Step 5: Once the engine starts, adjust the low-speed screw until the idle is as slow as possible without stopping the
This will give the maximum rich setting at low RPM.
Step 6: Hold the throttle wide open (with the rear tire off the ground) and adjust the high-speed screw to achieve
the engine has sufficient lubrication when running at high speed.
As a general rule, for almost all carburetors and valves, to increase the flow (make a "richer" mixture) when the
instructions say "out" or "open" or "unscrew" that means to rotate the jet counter-clockwise (like opening a jar of
peanut butter!). When you open the faucet to make water flow through a hose to water plants in your backyard, you
valve handle counter-clockwise. Both the high- and low-speed jets on your Go-Ped carburetor work like tiny valves to
control the amount of fuel flowing through the idle and high-speed passages in the carburetor. Turning the jet screws
clockwise closes the jets (produces a "leaner" setting); turning the jets counter-clockwise opens the jets (produces a
"richer" setting). Remember, closing means clockwise, and opening means counter-clockwise.
Repeat steps 5 through 7 until you get a steady idle, smooth throttle transition, and maximum RPM.
Tip: If the throttle butterfly does not close fully after you have finished installing the carb, try the following
To get the throttle to return to idle properly, you may need to adjust the angle of the bracket holding the throttle
cable to the carb. The object is to make sure that the cable inside the sheath slides freely when it comes out of the
end closest to the carb. By adjusting the angle of the bracket you will find a position where the cable will not rub
against the inside of the sheath.