What is carbon monoxide?
Carbon monoxide (CO) is an invisible, odorless, colorless gas created when fossil fuels (such as gasoline, wood, coal,
propane, oil and methane) burn incompletely. In the home, heating and cooking equipment are possible sources of
carbon monoxide. Vehicles running in an attached garage could also
produce dangerous levels of
carbon monoxide.
However, consumers can protect themselves against CO poisoning by maintaining, using, and venting heating and cooking equipment and by being cautious when using vehicles in attached garages.
Sure gasoline engines are known for not burning completely, because of their design. Everyone has seen tail pipes dripping gasoline at one time or another.
But in reality.... it's pretty difficult to feed a coleman stove with propane and not burn all of the propane. In fact... I'm not sure how you would accomplish that if you really tried to.