THE QUICK ANSWER
On a conventional carburettor choke, choke ON means the air restriction is applied: the choke is closed for cold starting. Choke OFF means the restriction is removed: the choke is open for normal running. An engine’s STOP / 0 control is a separate function.
Translate the label into airflow
For a conventional choke plate, “choke on” means the restriction is applied. The closed plate reduces incoming air for cold-start enrichment. “Choke off” means the restriction is removed and the plate is open for normal operation.
This is why “closed” does not mean “engine off”. It describes the choke, not the ignition. Keep that distinction in mind when reading a control marked with a combination of words, lines and symbols.
| Wording | Conventional choke meaning | A separate question |
|---|---|---|
| ON / closed / cold start | Choke restriction applied | How this particular engine should be started |
| OFF / open / run | Choke restriction removed | Whether the engine is running correctly |
| STOP / 0 | An engine stop or ignition function | Not the same thing as closing the choke |
Why the symbol can be confusing
A pictogram may represent the plate viewed from one direction, while the lever moves in a direction that is not obvious from the drawing. Do not infer “push left” or “move up” from the general explanation above.
Locate the model-specific control diagram and compare the actual lever positions. Automatic chokes and other enrichment systems may not have a manual open/closed control at all. The airflow diagram on this page explains an idea; it is not a label to copy onto an unidentified machine.
A documented STIHL example
The MS 311 / MS 391 instructions distinguish the normal run position I, a starting-throttle position, a closed-choke cold-start position, and Stop 0. Those are separate control states, even though one lever is involved.
That example helps explain the vocabulary. It is not a starting procedure for a different STIHL product or another engine brand. Use the complete instructions, including the safe starting position and equipment-specific precautions, for the machine in front of you.
Cold starting is different from stopping
Briggs & Stratton’s linked engine document gives an example of a closed choke during starting and progressively opening it as the engine warms. It also describes a separate stop function. The exact timing and controls depend on the engine.
Do not use a generic instruction about choking as a substitute for the correct stop procedure. Keep the engine’s emergency and normal stopping controls identified before attempting to start it.
If the engine only runs with the choke on
That observation is useful to report, but it does not identify a single failed part. Record whether it happens cold or warm and which marked position keeps the engine running. An engine needing continued enrichment after warm-up warrants model-specific troubleshooting.
Avoid speculative carburettor adjustments, removing guards while running, or testing a fuel-burning engine in an enclosed space. The next useful step is to match the symptom to the exact engine, not to keep operating it in a misunderstood control position.
The useful takeaway
Translate the label into a function: cold-start enrichment versus normal running. Do not infer the lever direction or the stopping procedure from a generic symbol alone.
Sources & scope
Manufacturer documentation and official guidance, checked 1 Nov 2026. This is a researched explanation, not a hands-on test or a manufacturer service bulletin. Match instructions to your exact model.
- STIHL — MS 311 / MS 391, starting and stopping the engine
Manufacturer’s distinction between STOP, normal run, starting throttle and the closed-choke cold-start position for these models.
- Briggs & Stratton — documented engine starting and stopping
A manufacturer example of starting with the choke closed and moving toward open as the engine warms; not an instruction for all current engines.