Jump to Section + Expand

The STIHL KM 94 R is a professional-grade KombiMotor, but its “simplified starting system” can be confusing if you are used to older 2-stroke engines. Whether you are using the KM 94 R or a similar model like the FS 94 RC-E trimmer, the starting procedure is identical.

Step 1: Set the Throttle Wheel

Before you pull the cord, look at the handlebar. Unlike many trimmers, the KM 94 R features a throttle set wheel that allows you to limit the engine speed. For a reliable start, ensure this is dialed toward the plus (+) sign.

Step 2: Prime the Engine

Locate the fuel primer bulb on top of the engine housing. Press the bulb firmly at least five times. Even if you see fuel already inside the bulb, continue to press it; this ensures the carburetor is fully purged of air and ready for combustion.

Step 3: Engage the Choke

To start the engine from a “cold” state (meaning it hasn’t been run in the last hour):

  1. Press the choke knob in.
  2. Turn it to the horizontal position (the Choke symbol).

Step 4: The Pull and the “Automatic” Pop

The KM 94 R features a “momentary” stop switch that is always in the On position, so you don’t need to flip a toggle.

  1. Place the unit on level ground.
  2. Pull the starter rope slowly until you feel resistance, then give it a short, brisk pull.
  3. Once the engine fires and stays running, briefly squeeze the throttle trigger.

Pro Tip: You will notice the choke knob physically pops back to the vertical “Run” position automatically when you hit the trigger. Do not try to force it back manually; let the machine do the work.

Video Walkthrough

If you want to see these steps in action and hear how the engine should sound, watch my full field test here:

Troubleshooting: What if it Won’t Start?

If you’ve followed these steps and the engine hasn’t turned over after 5 or 6 pulls, you may have a flooded engine. Here is how to fix it:

  • Check the Stop Switch: While it is designed to stay “On,” ensure no debris is jamming the spring-loaded button.
  • Clear a Flood: Move the choke knob to the vertical Run position. Hold the throttle trigger down completely (wide open) and pull the starter rope 5–10 times. This forces air into the combustion chamber to clear out excess fuel.
  • Check the Spark Arrestor: If the engine starts but bogs down or lacks power, the small screen in the muffler might be carbon-clogged.

Compatibility Note

This guide is also accurate for several other STIHL models that share this engine platform and starting system, including:

  • STIHL FS 94 / FS 94 R (String Trimmer)
  • STIHL HL 94 (Hedge Trimmer)
  • STIHL SP 92 (Special Harvester)

Gear Lab

Tagged in:

,