On the ground, at 70PPM for 20 minutes you will start to experience a
headache. 30PPM @ 20 minutes should not be a problem unless you're
climbing to ~ 8000 or are a smoker or suffer from some respiratory
malady or are in a constant state of inactivity (a lazy *******) . I
would first look real hard for any openings in your firewall to seal
and from there go to any exhaust compromise. I would then have the
ignition and carburetion systems checked to determine why you're
burning so dirty.

For those who aren't able to think, although 30 ppm at the exhaust
pipe isn't high, that much leak into the cabin indicates a bigger
problem at the dump. And as CO is a byproduct of the incomplete
combustion of a fossil fuel, it indicates something amiss in the
cylinders.

On Thu, 01 Apr 2004 23:31:51 -0600, "O. Sami Saydjari"
wrote:

I purchased a C0 Experts Model 2002 about 1 month ago (it is quite
precise and I am generally pleased with it). When I am climbing out
from take-off, I am experiencing relatively high readings of CO, on the
order of 30 Parts Per Million (PPM). This only lasts about 20 minutes
or so. At cruise, it drops to below 10 PPM (considered normal).

(a) Does anyone else have any hard data about their CO concentration
levels in various phases of flight?

(b) I have read that anything above 10 PPM should be checked by an A&P,
but I have read elsewhere that something like 30PPM for short periods is
not a big deal. Are there any medical-types out there that can weigh in
on this issue?