Honda HRA21 Owner's Manual page 15

STARTING THE ENGINE
* Exhaust gas contains poisonous carbon monoxide.
Never run the mower in an enclosed area. Be sure
to provide adequate ventilation.
1. Move the throttle lever to "CHOKE".
NOTE:
Do not use "CHOKE"
when the engine is warm or
the air temperature is high. Move the throttle to
"LO" instead.
2. Turn the fuel valve "ON".
CHOKE
HROTTLE LEVER