Sydney Hoeltzli wrote in message ...
snip
Ground ran with brutal leaning afterwards and checked
all chts/egts on both, r and l mag. r mag ran rougher,
with higher EGT on #4 cyl.

Suggestions? Going out to clean plugs and make sure
all 4 cyl have compression this afternoon, what else
to check? I'm hoping for a badly fouled plug, but
would that produce high EGT on 1 mag?

Puzzling! It sounds like a bad or fouled plug, but the EGT doesn't
make sense. If you were running on both mags, a bad plug would show
up as a higher EGT on that cylinder. If you switched to the rough
running mag, the EGT for the bad plug should drop. Running on a
single (good) plug causes the EGT to rise since the fuel air mixture
doesn't burn as quickly and is still burning when ejected into the
exhaust. If you're running on a single plug that is firing
intermittently, I'd expect the overall EGT to be lower, since there
are (cold) unburned charges exiting the cylinder.

Could the high EGT reading be coming from unburned charges being
ignited in the exhaust stack by subsequent burning charges?

John Galban=====N4BQ (PA28-180)


BTW I envy the chap in the other thread who posted about
"continuing as normal as possible" because an engine w/
a blown valve will continue to make normal power for
a long time. Personally when my engine is running rough
I'm not capable of such savoire-faire, I operate on the
assumption that I really don't know what's up and the
b**ch may quit on me any second. I want as much energy
as I can bank until I have the runway made.

Cheers,
Sydney