We have the same detector in our 172 N and I have never seen any CO even
though we have doors that don't fit very well. The memory function
sometimes shows a zero hour, 30 - 40 peak from startup but that's all we've
seen in two years.

I and several other club members run the engine slightly LOP. (Yes, you
actually can do this with a simple engine if the induction system is tight
and the ignition system is good.) One advantage of this is minimal CO
production.

--

Roger Long