Trimmer throttle stuck or sticking

Symptoms

• Engine stays at high RPM after releasing the trigger
• Throttle trigger feels stiff or catches partway
• Trigger doesn't spring back on its own
• Engine revs unexpectedly on its own

Likely causes

• CommonDirt or debris in the throttle trigger housingGrass clippings and dust can build up around the trigger mechanism and cause binding.
• CommonGummed-up throttle cableOld lubricant or dirt inside the cable housing increases friction along its length.
• PossibleBroken or weak return springThe spring that pulls the throttle back to idle can weaken or snap over time.
• PossibleBent throttle linkage at the carburetorPhysical damage to the linkage can cause it to bind at certain positions.
• Less commonFrayed cable catching in the housingA fraying cable strand can snag inside the outer housing.

What to do

1. Immediately stop the engine using the kill switch if the throttle sticks during use, since this is a safety hazard.
2. With the engine off, clean debris out of the trigger housing and around the throttle lever.
3. Work the trigger by hand repeatedly to check for smooth, full-range movement without catching.
4. Inspect the throttle cable where it enters the carburetor for kinks, fraying, or stiffness.
5. Apply a small amount of cable lubricant into the cable housing if movement feels gritty.
6. Check the return spring at the carburetor linkage for proper tension and replace if weak or broken.
7. Do not operate the trimmer again until the throttle reliably returns to idle on its own every time.

Tools and parts

• Small brush
• Cable lubricant
• Needle-nose pliers

When to call a pro

If cleaning and lubricating don't fix a sticking throttle, or the linkage is bent, have a small-engine shop repair it before using the trimmer again.

Safety