On Sep 7, 10:35*pm, Andy wrote:
On Sep 7, 6:27*pm, Kurt wrote:

We have 2 Pawnee's, both 235 HP fixed prop. *One has a problem with
carbon monoxide. *

Are you using the same measurement instrument in both aircraft? (not
the same type but actually the same instrument)

I fly 2 Pawnees at my club but I don't think either has a CO monitor.
Maybe I'll borrow one for my next tow duty.

Andy

Mix up a big bucket of soapy water using dishwashing detergent, get a
rubber ball that fits the exhaust stack outlet to plug it, with the
mags COLD, and the engine cut off by leaning the mixture, wet down the
exhaust system, have a couple of guys hold the prop,remove one spark
plug per jug and do a "compession check" with the exhaust valve open,
if you have cracks, just look for the bubles...