Hedge Trimmer: Blades Don't Oscillate

Your trimmer’s blades are designed to oscillate, which allows them to cut whatever plants you are intending to trim. As a result, the blades can become clogged with debris including sap, dirt, and smaller branches. This can cause the blades to seize. Proper maintenance and lubrication of your hedge trimmer’s blades will usually prevent this from occurring. A good degreaser cleaner will help fix this problem and sometimes you may be able to use a small screw driver or brush to remove any build up you come across. Water should not be used to clean your blades, as it may cause rust to form. You may also want to check the point at which the blades are attached to the gear inside the gear housing for any wear or broken parts. This may cause one or more of the blades to become unable to move as well.

The gear case is attached underneath the engine and near where the blades are located. The purpose of the case is to prevent debris from getting into the gears and ultimately damaging them or causing them to malfunction. The gear case is also a barrier between the trimmer’s operator and the unit’s moving parts that can cause injuries. If the gear case becomes damaged it can put pressure on the moving parts inside and potentially stop the transfer of power from the engine to the blades. This can result in a lack of oscillation in the blades.

The gear on your hedge trimmer is found in the gear housing under the engine, between the clutch and the 2 blades. During operation, a properly functioning gear will spin using specially designed teeth that transfer power to the blades, allowing them to move back and forth. If this gear becomes worn or broken in any way it will not transfer power, and therefore the blades will not oscillate. To replace the gear, first remove the blade assembly to locate the gear between the blades. If you inspect the gear and discover it is worn or broken. If this is the case, replace the gear and the blades should oscillate properly again.

The clutch is located on the engine’s crankshaft. It is designed to transmit power from the engine to the gears, which allows the blades to oscillate. The input of the clutch is attached to the engine’s crank shaft and the output shaft may be drive a shaft, belt, or chain (depending upon the model of trimmer you own). Over time clutches tend to become worn and as a result, they can start to slip. When the clutch slips, the blades will not oscillate properly, and may not move at all. To replace the clutch, you will have to remove the engine from the gear housing assembly. Depending on your model, you may be able to remove the clutch by using a clutch removing tool. When completing this repair, be sure to disconnect the spark plug so your machine doesn’t accidentally start up when your fingers are near the moving pieces. You will also want to make sure piston is at bottom dead center, and can then stick a cord inside the spark plug hole to keep the piston from moving.