DIY repair
How to adjust a 2-cycle carburetor
Most Huztl carburetors run perfectly as they come out of the box. But engines wear, altitudes differ and a long-stored trimmer sometimes wants a small nudge. Here is how we set the screws on our own bench.
- 01
Warm the engine up
Start the engine and let it idle for two to three minutes with a clean air filter fitted. Adjusting a cold engine gives you a setting that will be wrong in five minutes.
- 02
Find the screws
Look for two or three screws near the throttle. H is high speed, L is low speed and the T or idle screw rests against the throttle lever. Many carbs have splined heads; use a matching tool.
- 03
Set the idle
Turn the idle screw until the engine idles smoothly without the trimmer head or chain moving. On most handhelds that is a quarter to half turn from where it stops.
- 04
Tune the low speed
Turn L slowly clockwise until the idle starts to drop, then back it out until the engine revs up cleanly when you squeeze the throttle. It should not stumble or hesitate.
- 05
Tune the high speed
At full throttle, turn H clockwise in small steps until the engine sounds crisp, then back it out an eighth of a turn. Never run an engine lean at full throttle; a slightly rich setting protects the piston.
- 06
Recheck idle
After H and L are set, check the idle again and correct it with the idle screw.
