Mooney Engine Problems in Flight

On Mon, 13 Dec 2004 07:42:08 -0600, "Dan Luke" wrote:


"Ron Rosenfeld" wrote:

It sure sounds like a problem with fuel flow.

Wouldn't a fuel restriction make the EGT go up?

If you lean your engine until it starts to run rough, what happens (both to
TIT as well as to the individual EGT's), is that the EGT initially rises,
then it reaches a peak and begins to fall.

So what happens to the EGT will depend on where you are on that curve, when
the engine begins to run rough.

I have had problems, over the years, with clogged injector; clogged fuel
line; and clogged fuel servo. In all of those instances, the EGT for the
affected cylinder(s) went down when engine roughness was noted. Except for
the fuel servo when the problem became evident on takeoff and I was
concentrating on landing, rather than looking at EGT's.


Ron (EPM) (N5843Q, Mooney M20E) (CP, ASEL, ASES, IA)

Ron Rosenfeld wrote:
I have had problems, over the years, with clogged injector; clogged
fuel
line; and clogged fuel servo. In all of those instances, the EGT for
the
affected cylinder(s) went down when engine roughness was noted.
Except for
the fuel servo when the problem became evident on takeoff and I was
concentrating on landing, rather than looking at EGT's.

I had a plug go bad and that cylinder's EGT actually went up. I never
understood that.

-Robert, M20F

"Robert M. Gary" wrote

I had a plug go bad and that cylinder's EGT actually went up. I never
understood that.

-Robert, M20F

Incomplete/slower combustion, gases still burning in the exhaust header- on
the way past the EGT sensor.
--
Jim in NC

Robert M. Gary wrote :
I had a plug go bad and that cylinder's EGT actually went up. I never
understood that.

If one plug in a two plugged cylinder quits working, then there is
only one flame front. Instead of the fuel/air charge burning from two
ignition sources, it burns from one. This results in the charge taking
longer to completely burn. Since the charge took longer to burn, the
gasses are still hotter when the exhaust valve opens and the gasses
pass by the EGT probe.

This will happen anytime you go from 2-plug to single plug operation.
When in cruise, switch to one mag or the other. You should see a rise
on all EGTs.

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

"Robert M. Gary" wrote:
I had a plug go bad and that cylinder's EGT actually went up. I never
understood that.

That's easy: failure of one plug prolongs the burning of the mixture, so
some is still burning as it is ejected out the exhaust past the temp.
probe.
--
Dan
C172RG at BFM

On 13 Dec 2004 15:10:43 -0800, "Robert M. Gary" wrote:

I had a plug go bad and that cylinder's EGT actually went up. I never
understood that.

That is what should happen. Has to do with flame fronts and burning time.

Assuming you have EGT monitors for each cylinder, watch what happens when
you do your mag check. EGT's in all cylinders will rise significantly.
AAMOF, that is one recommended method (in the Insight GEM manual) given for
checking.


Ron (EPM) (N5843Q, Mooney M20E) (CP, ASEL, ASES, IA)

Paul Smedshammer wrote:
This is a bit long winded but I'm looking for qualified opinions as
to what
might have happed to an almost total loss of power while in cruise
flight in
my Mooney M20F. Here is the story of what happened:

I also own an M20F. Did you have teh ram air on? There are cases of ice
build up when the ram air is on. The owner's manual cautions us to turn
it off in ice conditions.

Have you checked your fuel vents? There have been reports of Mooneys
lossing power after fuel vent blocks. However, changing tanks should
fix that.

The Mooney does have an automatic alternate air system. At annual, the
automatic switching door should be inspected and the spring pressure
should be measured.

-Robert, M20F

In article .com, "Robert M. Gary" wrote:

Paul Smedshammer wrote:
This is a bit long winded but I'm looking for qualified opinions as
to what
might have happed to an almost total loss of power while in cruise
flight in
my Mooney M20F. Here is the story of what happened:

I also own an M20F. Did you have teh ram air on? There are cases of ice
build up when the ram air is on. The owner's manual cautions us to turn
it off in ice conditions.

Have you checked your fuel vents? There have been reports of Mooneys
lossing power after fuel vent blocks. However, changing tanks should
fix that.

The Mooney does have an automatic alternate air system. At annual, the
automatic switching door should be inspected and the spring pressure
should be measured.

-Robert, M20F

When this happened I had the power boost off. As one of the trouble shooting
items I opened it and got a slight increase in power like from 30% to 35%.
Hard to judge but it was running extremely rough and opening the power boost
cleaned it up just a little bit. I left it open as it did make things just a
little better. But it was the enriching of the mixture that really made the
difference. Still less than 50% power but it at least ran smoother.

By the way, I LOVE this plane. It is old but it fly's great and I feel the
most comfortable I have ever felt in about 7 different planes types (152, 172,
172RG, 182, Debonair, Warrior, and Arrow). The Mooney just has the
performance I have always been wanting. It is a great plane... as long as the
engine keeps running!

Paul, 1967 M20F

Paul Smedshammer wrote:
In article .com,
"Robert M. Gary" wrote:
When this happened I had the power boost off. As one of the trouble
shooting
items I opened it and got a slight increase in power like from 30% to
35%.

Do you know if your shop has done the AD that requires checking the
drain holes in the ribs? Since Mooney stores it's fuel in the wing
(rather than in a real fuel tank), the fuel needs to run through the
ribs. At the bottom of the ribs there are very small holes. When the
tank gets patched its easy to put your B-2 over these holes and create
a small pocket where fuel (and water) can stay trapped for some time.
Some of these holes should be covered (since they are mating points
that can allow fuel leaks) and others are there on purpose (to allow
water and fuel to run through). I wonder if you might have disloged
some water in your flight. Turning on the pump would increase the
amount of fluid running through the system and maybe move the water out
sooner? Just a guess.
-Robert, Mooney CFI and M20F owner (and loving it!!)

In article .com, "Robert M. Gary" wrote:

Paul Smedshammer wrote:
In article .com,

Thanks to everybody for your responses. Sounds like the general consensus is
either water in the fuel or some other fuel contamination. I'm taking the
plane up to LASAR to have them drain the tanks and go through the whole fuel
system. Hopefully they can find something that would explain what happened.
This sure makes me think twice about VFR on top or even night flying.

Paul,
1967 Mooney M20F