RST Engineering wrote:

And I read in another thread where he wanted to "sniff for CO" with the
airplane at various angles to the wind?

Repeat after me very carefully ... Carbon monoxide is a colorless gas with
no perceptible odor.

Kneaux news there...

Now it is true that CO is generally mixed with other exhaust gases which DO
have an odor, but that's not always true.

If the visual inspection of the stacks, the muffler and the shroud show
absolutely no evidence of exhaust gas leakage, tell me how in hell he
expected any gas leakage into the cabin?

Commercial CO Monitor with a wand (rigid tubing) attached...