How to adjust a tillotson carburetor

The Tillotson carburettor is used on small engines designed primarily for go-karts. You can adjust the carburettor in just a few minutes. The carburettor uses a low-speed and high-speed set screw that you can adjust fairly easily with just a screwdriver.

The high-speed set screw includes a "T" on the end, allowing you to adjust the screw by hand.

Locate the idle set screw at the very bottom of the Tillotson carburettor. Turn it clockwise with a screwdriver until you completely close it without over-tightening the screw.

Find the low-speed adjustment screw with the "L" next to it on the carburettor body. Turn the low-speed screw all the way clockwise and back it out counterclockwise one and a half turns.

  • The Tillotson carburettor is used on small engines designed primarily for go-karts.
  • Find the low-speed adjustment screw with the "L" next to it on the carburettor body.

Locate the high-speed adjustment screw with the "H" on the body. Turn the high-speed screw all the way clockwise and back it off counterclockwise three-quarters of a turn.

Start the motor and let it warm up for a few minutes. If the engine is having trouble starting, adjust the low-speed screw just a bit to get it started.

Turn the low-speed screw until you can hear the motor slow down. Adjust the screw as slow as you can get the engine to run without stalling out.

  • Locate the high-speed adjustment screw with the "H" on the body.
  • Turn the low-speed screw until you can hear the motor slow down.

Open the carburettor throttle all the way and adjust the high-speed screw as high as it will go while still running smoothly. Turn the high-speed screw back one-eighth and shut off the engine.

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