AFAIK CO poisoning is cumulative. i.e. being exposed to low levels for a long period is the same as exposed to a high level for a short period. Once a red cell has absorbed the CO - which apperently it does so far more readily and in preference to O2, it is effectively u/s until it dies and is replaced by a fresh cell generated from your bone marrow (or something like that.....) which takes days or longer.....(I am not a doctor so I may be wrong)

A friend of mine who is ex SAS once explained to me how they can make a car explose with a handle of household items, inserting them in the exhaust and then blocking with a banana.

I would have thought the exhaust system is a sealed unit

Some people are more sensitive than others to low concentrations of CO. Air cooled engines usually run pretty rich But even after spending a couple of hours with the chainsaw belching CO and HC straight into my face I can't say I feel any different. But then I smoke so my bloodstream always contains CO...

You're absolutely right unthrottled. I'm sensitive to that sort of thing. Very good sense of smell - of course that can sometimes be a disadvantage :)

Edited by corax on 11/02/2013 at 14:10