Generator starts but immediately stalls within a few seconds; no code is logged.

Safety first: Disable auto-start and keep hands clear of moving parts.

• Check fuel cap vent: Loosen the fuel cap slightly and attempt to start. If the engine runs longer, the cap vent may be blocked; replace the cap.
• Inspect choke operation: On cold start, verify that the choke plate closes and then opens gradually as the engine warms. Repair or replace the choke actuator if stuck.
• Clean carburetor/throttle body: Remove the air filter and spray carburetor or throttle body cleaner into the intake while cranking (do not overspray). If the engine runs only on cleaner, the fuel circuit is restricted.
• Check speed sensor connection: Ensure the engine speed sensor connector is secure; intermittent feedback can cause the controller to shut the engine down.