Leaning for taxi

[Jim Rosinski]

Earlier this summer I had a problem with a 400 rpm or so mag drop
during runup. Leaning aggressively at 2100 rpm solved the problem, but
it recurred on numerous occasions. I tried leaning aggressively during
all taxi operations, to the point that the engine would barely run,
and that seems to have solved the problem. No unacceptable mag drop
now for the past month. And a lower throttle setting can be used to
achieve the same taxi rpm as in the past, where the leaning procedure
was "pull the mixture out an inch or so from full rich" (my home base,
2V2, is just over 5000 feet elevation). But I still use the same "lean
to peak rpm then enrichen slightly" pre-takeoff procedure as I always
have at this altitude.

What do folks think of this procedure? Can it harm the engine? It's a
Lycoming O320-D2G in a Skyhawk. Thanks in advance.

Jim Rosinski
N3825Q

[Michael 182]

Hi Jim,

I'm at 2V2 as well. I lean for taxi in my TR-182, (IO-540) although not as
aggressively as you seem to. Full rich for takeoff, because of the turbo.

By the way, I'm always looking for a safety pilot if you want to trade some
time...

Michael


"Jim Rosinski" > wrote in message
om...
> Earlier this summer I had a problem with a 400 rpm or so mag drop
> during runup. Leaning aggressively at 2100 rpm solved the problem, but
> it recurred on numerous occasions. I tried leaning aggressively during
> all taxi operations, to the point that the engine would barely run,
> and that seems to have solved the problem. No unacceptable mag drop
> now for the past month. And a lower throttle setting can be used to
> achieve the same taxi rpm as in the past, where the leaning procedure
> was "pull the mixture out an inch or so from full rich" (my home base,
> 2V2, is just over 5000 feet elevation). But I still use the same "lean
> to peak rpm then enrichen slightly" pre-takeoff procedure as I always
> have at this altitude.
>
> What do folks think of this procedure? Can it harm the engine? It's a
> Lycoming O320-D2G in a Skyhawk. Thanks in advance.
>
> Jim Rosinski
> N3825Q

[The Weiss Family]

"Jim Rosinski" > wrote in message
om...
> Earlier this summer I had a problem with a 400 rpm or so mag drop
> during runup. Leaning aggressively at 2100 rpm solved the problem, but
> it recurred on numerous occasions. I tried leaning aggressively during
> all taxi operations, to the point that the engine would barely run,
> and that seems to have solved the problem. No unacceptable mag drop
> now for the past month. And a lower throttle setting can be used to
> achieve the same taxi rpm as in the past, where the leaning procedure
> was "pull the mixture out an inch or so from full rich" (my home base,
> 2V2, is just over 5000 feet elevation). But I still use the same "lean
> to peak rpm then enrichen slightly" pre-takeoff procedure as I always
> have at this altitude.
>
> What do folks think of this procedure? Can it harm the engine? It's a
> Lycoming O320-D2G in a Skyhawk. Thanks in advance.
>
> Jim Rosinski
> N3825Q

A buddy at work and I are both pilots, and we rent two different Skyhawks.
He told be about a similar experience.
His instructor (and owner) told him that a plug in one cylinder kept
fouling, and at runup, put it up to 2500 for 20 seconds to clear it out.
I don't know if this is at all similar, but just rang a bell for some
reason...

Adam

[Bob Gardner]

"Full rich for taxi" is an anachronism. Always lean for taxi.

Bob Gardner

"Jim Rosinski" > wrote in message
om...
> Earlier this summer I had a problem with a 400 rpm or so mag drop
> during runup. Leaning aggressively at 2100 rpm solved the problem, but
> it recurred on numerous occasions. I tried leaning aggressively during
> all taxi operations, to the point that the engine would barely run,
> and that seems to have solved the problem. No unacceptable mag drop
> now for the past month. And a lower throttle setting can be used to
> achieve the same taxi rpm as in the past, where the leaning procedure
> was "pull the mixture out an inch or so from full rich" (my home base,
> 2V2, is just over 5000 feet elevation). But I still use the same "lean
> to peak rpm then enrichen slightly" pre-takeoff procedure as I always
> have at this altitude.
>
> What do folks think of this procedure? Can it harm the engine? It's a
> Lycoming O320-D2G in a Skyhawk. Thanks in advance.
>
> Jim Rosinski
> N3825Q

[Ben Jackson]

In article >,
Jim Rosinski > wrote:
>I tried leaning aggressively during
>all taxi operations, to the point that the engine would barely run,

I started doing this when I bought my plane. Eventually I quit pushing
the mixture to full rich at start. I only push it in about an inch now
when it first catches, and I don't advance it until I do the runup.

--
Ben Jackson
>
http://www.ben.com/

[Casey Wilson]

"Jim Rosinski" > wrote in message
om...
> Earlier this summer I had a problem with a 400 rpm or so mag drop
> during runup. Leaning aggressively at 2100 rpm solved the problem, but
> it recurred on numerous occasions. I tried leaning aggressively during
> all taxi operations, to the point that the engine would barely run,
> and that seems to have solved the problem. No unacceptable mag drop
> now for the past month. And a lower throttle setting can be used to
> achieve the same taxi rpm as in the past, where the leaning procedure
> was "pull the mixture out an inch or so from full rich" (my home base,
> 2V2, is just over 5000 feet elevation). But I still use the same "lean
> to peak rpm then enrichen slightly" pre-takeoff procedure as I always
> have at this altitude.
>
> What do folks think of this procedure? Can it harm the engine? It's a
> Lycoming O320-D2G in a Skyhawk. Thanks in advance.
>
Summertime density altitude at KEDW is almost always over 5Kft.
We pull the mixture out before we leave the chocks.

[Scott D.]

On 5 Sep 2004 16:46:24 -0700, (Jim Rosinski) wrote:

>What do folks think of this procedure? Can it harm the engine? It's a
>Lycoming O320-D2G in a Skyhawk. Thanks in advance.
>
>Jim Rosinski
>N3825Q

Here are COS (elv 6100), we don't even start the engine at full rich.
We keep it about an inch out when we crank up on the 172's. Then I
even lean it a little more for the taxi. then I perform the run up and
lean as recommended. I have yet seen a fouled plug on run up doing
this in over 2 years.

Scott D,

[Brien K. Meehan]

You may have an ignition problem occurring that is being masked by
running the engine for a while, so that it appears that running lean
for a while clears it up. You may want to have your plugs tested at
your next oil change (or sooner).

[Thomas Borchert]

Jim,

> What do folks think of this procedure? Can it harm the engine?
>

Good procedure. You cannot harm an engine by leaning it during taxi.

You might want your mechanic to adjust idle mixture. If, at idle, you
pull out the mixture slowly, you should see a 25 to 50 rpm rise in RPM
just before the engine quits - that's the correct setting. OTOH, if you
adjust it for your field altitude, you might have problems at lower
altitude fields.

--
Thomas Borchert (EDDH)

[Jay Honeck]

>> What do folks think of this procedure? Can it harm the engine? It's a
>> Lycoming O320-D2G in a Skyhawk. Thanks in advance.

Can you get the autogas STC for that engine?

We had the O320 in our Warrior, and unleaded autogas completely eliminated
failed mag checks, and the need to lean over-aggressively.

And, of course, it saves you ten bucks an hour.
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

[james rosinski]

Jay Honeck wrote:

>>What do folks think of this procedure? Can it harm the engine? It's a
>>Lycoming O320-D2G in a Skyhawk. Thanks in advance.
>
> Can you get the autogas STC for that engine?
>
> We had the O320 in our Warrior, and unleaded autogas completely eliminated
> failed mag checks, and the need to lean over-aggressively.

No, the D2G engine is higher compression and requires 100 octane. The
upside is you get 10 more horses (160 vs 150).

Maybe just as well to not mess with autogas out here anyway. Flying in
the nearby mountains can require climbing to 13,000 feet or higher, and
I've heard auto gas is more prone to vapor lock at high altitudes. I'm
no expert though, and haven't done any further research since it's a
moot point for my plane anyway.

Jim Rosinski
N3825Q

[Robert M. Gary]

"Bob Gardner" > wrote in message >...
> "Full rich for taxi" is an anachronism. Always lean for taxi.

The test pilot for Mooney said the lawyers made them put that on the
checklist because they were afraid someone would forget and take off
with the mixture leaned. However, if you lean properly, you could
never get anywhere near takeoff power when leaned. I lean so that
additional throttle does not cause any increase in RPM. It took me 3
plug cleanings to figure this out. I've now never had a plug cleaned
outside of annual.
-Robert

[Jay Honeck]

> Maybe just as well to not mess with autogas out here anyway. Flying in the
> nearby mountains can require climbing to 13,000 feet or higher, and I've
> heard auto gas is more prone to vapor lock at high altitudes. I'm no
> expert though, and haven't done any further research since it's a moot
> point for my plane anyway.

Wow -- you climb a Warrior to 13,000 feet?

I never took mine higher than 11.5 -- and THAT was in the winter. And it
took forever to get there.

In the summer, even the longest journey would be over before I reached 8,500
feet...
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

[Morgans]

"Jay Honeck" > wrote >
> Wow -- you climb a Warrior to 13,000 feet?
>
> I never took mine higher than 11.5 -- and THAT was in the winter. And it
> took forever to get there.
>
> In the summer, even the longest journey would be over before I reached
8,500
> feet...
> --
> Jay Honeck

Think JATO, Jay, JATO!!!!!
--
Jim in NC


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[jim rosinski]

Jay Honeck wrote:

> Wow -- you climb a Warrior to 13,000 feet?
>
> I never took mine higher than 11.5 -- and THAT was in the winter. And it
> took forever to get there.
>
> In the summer, even the longest journey would be over before I reached 8,500
> feet...

Nope--Skyhawk. In addition to the 160 hp engine it's got a powerflow
exhaust. As a guess I'd say that brings the available sea level horses
to something like 170 or 175. It makes a big difference.

Jim Rosinski
N3825Q

[Bela P. Havasreti]

On Mon, 06 Sep 2004 00:36:11 GMT, tony roberts >
wrote:

Agreed.

The only time the mixture goes forward is when I pull out on the
runway for takeoff, and on short (SHORT) final (in preparation for
a go-around). This is in a '54 C-170B (C-145-2).

You can't hurt these engines by aggressive leaning at low power
settings (worse thing that can happen is you'll put the fire out and
she'll quit).

Bela P. Havasreti

>> What do folks think of this procedure? Can it harm the engine? It's a
>> Lycoming O320-D2G in a Skyhawk. Thanks in advance.
>
>Hi Jim
>I always aggressively lean my 0300D while taxiing.
>At those RPM's you will not overheat the engine.
>Check threads on this in the Cessnaa Owners Group.
>
>Tony

[Bela P. Havasreti]

On Sun, 05 Sep 2004 23:05:18 -0600, Scott D. <> wrote:

I do the same thing at sea level (only push the mixture in
1/2 an inch or so to start it, I start it lean and it stays lean until
I pull out onto the runway for take off).

Bela P. Havasreti

>On 5 Sep 2004 16:46:24 -0700, (Jim Rosinski) wrote:
>
>>What do folks think of this procedure? Can it harm the engine? It's a
>>Lycoming O320-D2G in a Skyhawk. Thanks in advance.
>>
>>Jim Rosinski
>>N3825Q
>
>Here are COS (elv 6100), we don't even start the engine at full rich.
>We keep it about an inch out when we crank up on the 172's. Then I
>even lean it a little more for the taxi. then I perform the run up and
>lean as recommended. I have yet seen a fouled plug on run up doing
>this in over 2 years.
>
>Scott D,

[Alan Bloom]

I have always started up my 182C 0-470 about 1" from full rich.
Then, always lean to taxi.
And, I lean at full power during run up. None of this girly man 1700
rpm stuff.

Alan Bloom
Dogs can fly.
http://www.flyingmutts.com




On 5 Sep 2004 16:46:24 -0700, (Jim Rosinski) wrote:

>Earlier this summer I had a problem with a 400 rpm or so mag drop
>during runup. Leaning aggressively at 2100 rpm solved the problem, but
>it recurred on numerous occasions. I tried leaning aggressively during
>all taxi operations, to the point that the engine would barely run,
>and that seems to have solved the problem. No unacceptable mag drop
>now for the past month. And a lower throttle setting can be used to
>achieve the same taxi rpm as in the past, where the leaning procedure
>was "pull the mixture out an inch or so from full rich" (my home base,
>2V2, is just over 5000 feet elevation). But I still use the same "lean
>to peak rpm then enrichen slightly" pre-takeoff procedure as I always
>have at this altitude.
>
>What do folks think of this procedure? Can it harm the engine? It's a
>Lycoming O320-D2G in a Skyhawk. Thanks in advance.
>
>Jim Rosinski
>N3825Q

[Bob Gardner]

If you forget to go to full rich for takeoff, the engine should quit (or at
least complain) when takeoff power is applied. I agree with "the lawyers
made me do it."

Bob

"Robert M. Gary" > wrote in message
om...
> "Bob Gardner" > wrote in message
>...
> > "Full rich for taxi" is an anachronism. Always lean for taxi.
>
> The test pilot for Mooney said the lawyers made them put that on the
> checklist because they were afraid someone would forget and take off
> with the mixture leaned. However, if you lean properly, you could
> never get anywhere near takeoff power when leaned. I lean so that
> additional throttle does not cause any increase in RPM. It took me 3
> plug cleanings to figure this out. I've now never had a plug cleaned
> outside of annual.
> -Robert

[David Brooks]

"Jim Rosinski" > wrote in message
om...
> Earlier this summer I had a problem with a 400 rpm or so mag drop
> during runup. Leaning aggressively at 2100 rpm solved the problem, but
> it recurred on numerous occasions. I tried leaning aggressively during
> all taxi operations, to the point that the engine would barely run,
> and that seems to have solved the problem. No unacceptable mag drop
> now for the past month. And a lower throttle setting can be used to
> achieve the same taxi rpm as in the past, where the leaning procedure
> was "pull the mixture out an inch or so from full rich" (my home base,
> 2V2, is just over 5000 feet elevation). But I still use the same "lean
> to peak rpm then enrichen slightly" pre-takeoff procedure as I always
> have at this altitude.
>
> What do folks think of this procedure? Can it harm the engine? It's a
> Lycoming O320-D2G in a Skyhawk. Thanks in advance.

I lean for taxi, but I did learn one lesson. On one occasion soon after I
started the practice, the engine quit when I applied power to get the wheels
rolling. The passenger wasn't impressed. Now I lean a little less.

-- David Brooks

[G.R. Patterson III]

james rosinski wrote:
>
> Jay Honeck wrote:
>
> >>What do folks think of this procedure? Can it harm the engine? It's a
> >>Lycoming O320-D2G in a Skyhawk. Thanks in advance.
> >
> > Can you get the autogas STC for that engine?
>
> No, the D2G engine is higher compression and requires 100 octane. The
> upside is you get 10 more horses (160 vs 150).

Petersen has an STC for the Skyhawk with the O-320-D2G.
http://www.autofuelstc.com/autofuelstc/pa/PetersenAviation.html

George Patterson
If you want to know God's opinion of money, just look at the people
he gives it to.

[jim rosinski]

G.R. Patterson III wrote:

> Petersen has an STC for the Skyhawk with the O-320-D2G.
> http://www.autofuelstc.com/autofuelstc/pa/PetersenAviation.html

So they do! Thanks for the pointer. Interesting reading--no ethanol
blends are allowed, and the STC for the D2G engine requires a minimum 91
octane rating. Reading the descriptions of airframes/engines that failed
certification tests due to "failed the vapor lock test" causes some
concern, particularly for the high altitudes I must often fly at.

Since self-serve 100LL is only $2.45 at my home base, the cost savings
of using premium mogas in a Skyhawk would be minimal. But it's nice to
know a simple STC is available in case the unthinkable happens--sources
of 100 octane avgas drying up.

N.B. there are LOTS of engine/airframe combinations mentioned on the web
site.

Jim Rosinski
N3825Q

[PaulH]

>
> I lean for taxi, but I did learn one lesson. On one occasion soon after I
> started the practice, the engine quit when I applied power to get the wheels
> rolling. The passenger wasn't impressed. Now I lean a little less.
>
> -- David Brooks

Despite your passenger's opinion, this is actually best practice since
it prevents you from taking off if you forget to enrich for the
takeoff. I know, I know, that's what checklists are for, but who
among us has never skipped an item on a checklist?

[Bob Martin]

> What do folks think of this procedure? Can it harm the engine? It's a
> Lycoming O320-D2G in a Skyhawk. Thanks in advance.


We're running an O-360 with an Ellison throttle-body injector... after start
we just pull the mixture nearly all the way out and taxi around like that
(the engine really doesn't like full rich on the ground). It stays there
till runup, and then after landing I usually lean out even before I clear
the runway. The RPM gain is significant when I do this; a full-rich idle
will sit somewhere between 500 and 600, and after leaning it will go to
around 900. With the mixture full out, you can get up to about 1300 RPM
before it starts to sag--this is good for clearing the plugs at the end of a
flight just before shutdown.

[Shkumbin Hamiti]

Hi,

I have learned from my intructor to lean for taxi, and I regularly do so. I
do so while waiting for take-off as well. One trick that I use (also learned
from my instructor) while waiting, is to place my checklist between throttle
and mixture, that way I don't forget to enrich. And also use my hand to push
everything forward at the same time (throttle, mixture, and with little
finger carb heat).
Usually fly Piper Cherokee 140MOD with 160HP Lycoming engine.

Regards,
Shkumbin, EFHF
PPL(A)-SEP,
Delete DELTA from email to reply.

P.S. Regarding skipping items from checklist: I have done it so in several
occasions, but once I got a bit scared during take-off roll. I skipped the
TRIM to Neutral item, and while on a take-off roll I got some "strange"
behaviour...the nose trim was at quite heavy Nose Up position. It took me
few seconds to realize that. For the moment I thought that the elevator got
somehow jammed. Since than I check the Trim three times at least...and never
skip an item from checklist. But I am still a novice, barely 100hours, so my
discipline will fade with time I guess...

"PaulH" > wrote in message
om...
> >
> > I lean for taxi, but I did learn one lesson. On one occasion soon after
I
> > started the practice, the engine quit when I applied power to get the
wheels
> > rolling. The passenger wasn't impressed. Now I lean a little less.
> >
> > -- David Brooks
>
> Despite your passenger's opinion, this is actually best practice since
> it prevents you from taking off if you forget to enrich for the
> takeoff. I know, I know, that's what checklists are for, but who
> among us has never skipped an item on a checklist?

[David Brooks]

"PaulH" > wrote in message
om...
> >
> > I lean for taxi, but I did learn one lesson. On one occasion soon after
I
> > started the practice, the engine quit when I applied power to get the
wheels
> > rolling. The passenger wasn't impressed. Now I lean a little less.
> >
> > -- David Brooks
>
> Despite your passenger's opinion, this is actually best practice since
> it prevents you from taking off if you forget to enrich for the
> takeoff. I know, I know, that's what checklists are for, but who
> among us has never skipped an item on a checklist?

Well, sure, it prevents you from taking off because you can only taxi 2 or 3
feet from the parking space, and never get to runup. You then have the wear
on the battery and started all over again.

But I take your point.

-- David Brooks

[Thomas Borchert]

David,

> Well, sure, it prevents you from taking off because you can only taxi 2 or 3
> feet from the parking space, and never get to runup.
>

How? it's real easy to lean to a point where you can taxi without problems but
not advance power to full. if you need full power for taxi, you have a
different set of problems...

--
Thomas Borchert (EDDH)

[David Brooks]

"Thomas Borchert" > wrote in message
...
> David,
>
> > Well, sure, it prevents you from taking off because you can only taxi 2
or 3
> > feet from the parking space, and never get to runup.
> >
>
> How? it's real easy to lean to a point where you can taxi without problems
but
> not advance power to full. if you need full power for taxi, you have a
> different set of problems...

Yes, but my point was it's also real easy to lean to past that point. That
was the scenario - I had leaned too well after startup and the engine
stopped after we had moved a few feet. Of course I can lean enough to allow
taxi, but I don't know of a way of getting the right setting for taxi while
I'm standing still. You have to use the TLAR (That Looks About Right)
method, which takes experience.

-- David Brooks

[Thomas Borchert]

David,

Well, i found it pretty easy to catch a stumbling engine by ust being
prepared and advancing the mixture a little.

--
Thomas Borchert (EDDH)