Shutting down engine Question

Take a look at our club operations manual for more on how we operate our
plane:

http://baldeagleflyingclub.org/Manual.htm

There is a section on running it lean of peak. Not all engines will do
this, even within the same make and model. Ours won't do it in all weather
conditions. When it works, its great though.

--
Roger Long

On Wed, 31 Mar 2004 10:25:02 GMT, "Roger Long"
om wrote:

This is the procedure we use on our O-320 and have had noticeably smoother
and quicker starts since we started it:

RPM - 1200
Lean for maximum RPM rise. (Don't worry, no amount of leaning will hurt the
engine at this low power)
Run 20 seconds
Throttle - Quickly to Idle
Mixture - Idle Cut Off
Switches - OFF

Leaning for all ground operations is vital to keep the mags clear on this
engine. On startup and after exiting the active runway, set RPM to 1000 and
lean slowly for maximum RPM rise. This will often be about 100. Lean
slightly past until RPM just starts to fall. If the engine runs a hair
rough, that's OK. It will be lean enough that it will start to stumble and
quit if you try to run it faster than about 1300. This means you can't
accidentally take off with it leaned.

Since we started doing this, I have only had to clear a mag a couple of
times in two years.

Roger Long

Roger, when you say "clear a mag" do you mean clearing plugs? Because
it isn't the mag that fouls, is it? Isn't it the plugs?

Thanks, Corky Scott

Yes, it is the plugs. Since you switch a mag off people often say clearing
a mag even though it's sort of like saying "digging a shovel".

Mags do foul for very different reasons but the only way to clear them is
with a wallet.

--
Roger Long

Roger, when you say "clear a mag" do you mean clearing plugs? Because
it isn't the mag that fouls, is it? Isn't it the plugs?

Thanks, Corky Scott

Lotsa "depends"... One of the benefits of owning a plane, or flying the
same one most of the time, is that you get to know the idiosyncrasies... On
mine, from experience I know the proper rpm for mixture cutoff that gives
the smoothest shutdown, and 99 times out of a 100 results in both props
stopping at the same angle... Just a game I play for my own satisfaction...
There is also the method of going to 1800-2000 rpm, pulling the mixture as
lean as it will go without shutting down, wait 10-15 seconds, then gently
close the throttle to idle, wait until the engine slows, then fully cut the
mixture... This helps to clear lead fouling off the plugs...
denny

"Lisa" wrote in message Which is best?

"Dennis O'Connor" wrote in message ...
Lotsa "depends"... One of the benefits of owning a plane, or flying the
same one most of the time, is that you get to know the idiosyncrasies... On
mine, from experience I know the proper rpm for mixture cutoff that gives
the smoothest shutdown, and 99 times out of a 100 results in both props
stopping at the same angle... Just a game I play for my own satisfaction...
There is also the method of going to 1800-2000 rpm, pulling the mixture as
lean as it will go without shutting down, wait 10-15 seconds, then gently
close the throttle to idle, wait until the engine slows, then fully cut the
mixture... This helps to clear lead fouling off the plugs...
denny

We run an O-360 with an Ellison TBI... the plugs tend to foul very
quickly, even if the engine is leaned during taxi. Therefore, our
shutdown procedure is to run up to about 1300 rpm and pull the mixture
out to right about peak. We let it run like that for 20-30 seconds,
then throttle back to about 800. Mixture is chopped to cutoff, then
we push the throttle up. As soon as it starts to speed up, we cut the
ignition off.

This process results in a clean start for next time, and the least
amount of shaking we've managed to accomplish without the engine
deciding to spin backwards for a few revs.

"Lisa" wrote in message ...
Perhaps this doesn't matter much for a non-turbocharged engine,
but an instructor says that it is best to idle the engine at
1,000 RPM for a few moments before Mixtu Idle Cut-Off at that
RPM to shut down.

The POH says throttle full aft, then mixture cut-off to shut
down.

I run at 1100 RPM just before shutdown, set the throttle
lock, and then pull the mixture back. This way, when I
restart on a cold day, I know that the engine will fire and
idle nicely at 700 RPM without overrevving or conking out.
This minimizes engine wear on startup.

Not sure I agree with posts (from Lycoming recommendation)
which suggest high RPM. Too much risk of damage to the
prop.

Yes, you will have more prop wear. However, if you have an O-320 H2AD, the
most vulnerable thing in the engine are the camshaft and lifters. Idling
below 1000 is hard on them because of reduced oil splash and higher metal
pressures. Better a $500 prop overhaul than the $8000 camshaft replacement
we just went through.

--
Roger Long

Tony Cox wrote in message
ink.net...
"Lisa" wrote in message
...
Perhaps this doesn't matter much for a non-turbocharged engine,
but an instructor says that it is best to idle the engine at
1,000 RPM for a few moments before Mixtu Idle Cut-Off at that
RPM to shut down.

The POH says throttle full aft, then mixture cut-off to shut
down.

I run at 1100 RPM just before shutdown, set the throttle
lock, and then pull the mixture back. This way, when I
restart on a cold day, I know that the engine will fire and
idle nicely at 700 RPM without overrevving or conking out.
This minimizes engine wear on startup.

Not sure I agree with posts (from Lycoming recommendation)
which suggest high RPM. Too much risk of damage to the
prop.

Lisa wrote in message ...
Perhaps this doesn't matter much for a non-turbocharged engine,
but an instructor says that it is best to idle the engine at
1,000 RPM for a few moments before Mixtu Idle Cut-Off at that
RPM to shut down.

The POH says throttle full aft, then mixture cut-off to shut
down.

Which is best?

The idle at 1,000 RPM sure helps in my IO-360 engine. My engine hot
starts great, and cold starts great, but is very hard to warm start.
Idling at 1,000 RPM (or 1,200 RPM) for a couple minutes seems to make
a huge difference.

-Robert

When we used to run Cessna 150s, we often found them hard to start.
Then we noticed that just after a flight, or lengthy runup before
inspection, that oil would dribble out of the bottom plug holes when
we pulled the plugs. These engines tend to foul the bottom plugs at
idle for some reason, and we instituted a 1700 RPM runup prior to
shutdown to clear them. No more hard starts or fouled plugs.
We have few fouling problems with the Lycs, other than with too
much circuit work.

Dan