hand-propping a 172SP

On Tue, 4 Mar 2008 11:07:24 -0800 (PST), Tom
wrote in
:

We tried after pumping the throttle.

As there is no carb pump, that is probably not a very useful
technique.

On Mar 4, 1:11 pm, "JGalban via AviationKB.com" u32749@uwe wrote:
Tom wrote:
Let me provide a couple more details:

The engine was hot - had just been flown for 1 hour, and had only been
off for maybe 15 minutes. The starter was malfunctioning in some way
but the battery was good. When I tried to start it with the starter,
it made a noise as though the starter motor was spinning but the
engine didn't crank.

I'll bet that was your problem with the hand prop attempt. Hot starts on
injected engines can take quite a few cranks even with a working starter.
Doesn't the 172 hot start procedure have the mixture lean, then you move it
to rich as the engine starts to catch? It would seem to be tough to
duplicate that with the engine turning one revolution at a time.

Your starter problem sounds like a sticky bendix gear. When the bendix
shaft gets gummed up, the bendix gear won't pop out and engage the ring gear.
It just spins. As you found, it will sometimes cure itself, but a permanent
fix involves cleaning and lubing of the bendix shaft. This is a common
problem on Cherokees, whose wacky design leaves the starter exposed to the
airstream (and all of the dirt, bugs and debris).

I usually carry some silicone spray lube and a very long, skinny
screwdriver (since I fly a Cherokee). If the bendix gear strands you, you
can always try dousing the bendix shaft with lube, then poking the bendix
gear a bit with the screwdriver. That's always worked for me.

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

--
Message posted via AviationKB.comhttp://www.aviationkb.com/Uwe/Forums.aspx/aviation/200803/1

A battery just a hair too low to run the starter would still
run the fuel boost pump. Starters consume several hundred amps,
causing a massive voltage drop in the system; a boost pump takes a few
amps and won't cause such a hassle.

Those sticky Bendix drives are often sticky because someone
used oil on them instead of silicone spray. The oil attracts dust and
sticky sludge forms.

Dan

On Mar 4, 3:11*pm, "JGalban via AviationKB.com" u32749@uwe wrote:
Tom wrote:
Let me provide a couple more details:

The engine was hot - had just been flown for 1 hour, and had only been
off for maybe 15 minutes. The starter was malfunctioning in some way
but the battery was good. When I tried to start it with the starter,
it made a noise as though the starter motor was spinning but the
engine didn't crank.

* I'll bet that was your problem with the hand prop attempt. *Hot starts on
injected engines can take quite a few cranks even with a working starter.
Doesn't the 172 hot start procedure have the mixture lean, then you move it
to rich as the engine starts to catch? * It would seem to be tough to
duplicate that with the engine turning one revolution at a time.

* *Your starter problem sounds like a sticky bendix gear. *When the bendix
shaft gets gummed up, the bendix gear won't pop out and engage the ring gear.
It just spins. * As you found, it will sometimes cure itself, but a permanent
fix involves cleaning and lubing of the bendix shaft. *This is a common
problem on Cherokees, whose wacky design leaves the starter exposed to the
airstream (and all of the dirt, bugs and debris).

* I usually carry some silicone spray lube and a very long, skinny
screwdriver (since I fly a Cherokee). *If the bendix gear strands you, you
can always try dousing the bendix shaft with lube, then poking the bendix
gear a bit with the screwdriver. *That's always worked for me.

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

--
Message posted via AviationKB.comhttp://www.aviationkb.com/Uwe/Forums.aspx/aviation/200803/1

Do airplanes with fuel injected engines still have a mixture knob? I
don't know the answer, but I would think not.

Wil

On Wed, 5 Mar 2008 20:23:14 -0800 (PST), William Hung
wrote:

On Mar 4, 3:11*pm, "JGalban via AviationKB.com" u32749@uwe wrote:
Tom wrote:
Let me provide a couple more details:

The engine was hot - had just been flown for 1 hour, and had only been
off for maybe 15 minutes. The starter was malfunctioning in some way
but the battery was good. When I tried to start it with the starter,
it made a noise as though the starter motor was spinning but the
engine didn't crank.

* I'll bet that was your problem with the hand prop attempt. *Hot starts on
injected engines can take quite a few cranks even with a working starter.
Doesn't the 172 hot start procedure have the mixture lean, then you move it
to rich as the engine starts to catch? * It would seem to be tough to
duplicate that with the engine turning one revolution at a time.

* *Your starter problem sounds like a sticky bendix gear. *When the bendix
shaft gets gummed up, the bendix gear won't pop out and engage the ring gear.
It just spins. * As you found, it will sometimes cure itself, but a permanent
fix involves cleaning and lubing of the bendix shaft. *This is a common
problem on Cherokees, whose wacky design leaves the starter exposed to the
airstream (and all of the dirt, bugs and debris).

* I usually carry some silicone spray lube and a very long, skinny
screwdriver (since I fly a Cherokee). *If the bendix gear strands you, you
can always try dousing the bendix shaft with lube, then poking the bendix
gear a bit with the screwdriver. *That's always worked for me.

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

--
Message posted via AviationKB.comhttp://www.aviationkb.com/Uwe/Forums.aspx/aviation/200803/1

Do airplanes with fuel injected engines still have a mixture knob? I
don't know the answer, but I would think not.

How the fuel enters the intake manifold and cylendars doesn't change
that the mixture needs to be adjusted. We're talking injected fuel
here, not FADEC.

On Wed, 5 Mar 2008 20:23:14 -0800 (PST), William Hung
wrote in
:

Do airplanes with fuel injected engines still have a mixture knob? I
don't know the answer, but I would think not.

You've never flown behind an injected engine?

Larry Dighera wrote in
:

On Wed, 5 Mar 2008 20:23:14 -0800 (PST), William Hung
wrote in
:

Do airplanes with fuel injected engines still have a mixture knob? I
don't know the answer, but I would think not.

You've never flown behind an injected engine?



I think he implied that, fjukkwit.


Bertie