Honda UMK435T Manuel De L'utilisateur page 16

To ensure safe operation
Carbon Monoxide Poisoning Hazard
Exhaust contains poisonous carbon monoxide, a colorless and
odorless gas. Breathing exhaust can cause loss of consciousness and
may lead to death.
If you run the engine in an area that is confined or even partially
enclosed, the air you breathe could contain a dangerous amount of
exhaust gas. To keep exhaust gas from building up, provide
adequate ventilation.
Replace faulty muffler.
Do not operate the engine in a confined space where dangerous
carbon monoxide fumes can collect.
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