Mooney Engine Problem in Flight - Advise

On 13-Dec-2004, zatatime wrote:

I think this is the correct "guess." Induction icing can occur in the
60 degree range without a problem if you have the right conditions
(i.e. moisture, which you had alot of). In your original post you
stated you put on an alternate air source of some sort to bypass the
air filter. Check with your mechanic if this gives heated air to the
mixture. If so this is the equivalent of carb heat, and could be how
the problem resolved itself. If not, check to see how to provide warm
air to the induction system. Even if you've got to make a
modification (install something), it'll be worth it.


Induction air heating is not required for injected engines because intake
air is not cooled like it is in a carburetor. Induction icing in an
injected engine means that frozen (i.e. snow) or super-cooled water in the
atmosphere freezes in the induction system (usually in the air filter) and
restricts airflow. The alternate air system bypasses the air filter to
solve the problem. Source of alternate air in most injected airplanes is
from within the cowling, so there is some warming effect. The Mooneys of a
certain vintage used their "Power Boost" system to double as the alternate
air, so their alternate air source is ram induction.

In this case induction icing as the problem is extremely unlikely for two
reasons. First, it is not likely to occur with an OAT in the 60 degree
range. Second, induction icing, or any other problem that restricts intake
air, would result in an excessively RICH mixture, and engine roughness would
then be reduced by LEANING the mixture. In this case engine roughness was
reduced by ENRICHING the mixture, which indicates that the problem lay not
in the intake air but in the fuel system. Water in the fuel is certainly a
possibility, but since the problem did not resolve by switching tanks
(assuming the pilot gave it a few moments for this to work before switching
back) I think a more likely culprit would be one or more partially clogged
injectors. I would have a mechanic inspect the fuel system from the
gascolator through the injectors to make sure that no contaminants remained.

--
-Elliott Drucker

In article 05mvd.4322$lZ6.4235@trnddc02, wrote:

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.

I will post what they hopefully find.

Paul,
1967 Mooney M20F

"Paul Smedshammer" wrote in message
om...
In article 05mvd.4322$lZ6.4235@trnddc02,
wrote:

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.

I will post what they hopefully find.

Paul,
1967 Mooney M20F

200hp Lycoming, right? Monitor each cyl head and egt individually. Only
4 to monitor. You can isolate the problem better that way. You may have
had a clogged injector or two or plugs failing or valves sticking or mag or
mags malfunctioning or harness cross-arcing, or ?. Full monitoring with
memory will keep your mags, plugs, harness, valves, cam, and injection
reasonably diagnosed, away from enigmas like this one, and you more
knowledgeable and happier. Read more Deakin too.

In article , (Paul Smedshammer) wrote:
In article 05mvd.4322$lZ6.4235@trnddc02, wrote:

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.

I will post what they hopefully find.


I just spent 4 hours of mechanic time up at Lasar. At my request they went
through everything. Checked the tanks for water, checked the gas collator,
servo, injectors, spark plugs, exhaust for blockage, air intakes (filter,
alternate air, ram air) all without finding anything. Test flight afterward
and the flight home both had the engine running perfectly as if nothing had
ever happened. Everybody is scratching their heads a little but I'm pretty
sure the culprit was water in the tank. On the flight that I had the trouble,
I made a step bank turn to stay under the fog ahead and I'm thinking there was
some water trapped behind a rib in the wing. The steep turn could have
stirred it up and had it settle to the bottom of the tank, which then got
pulled into the engine. It ran really rough for a while as it was a mixture
(recently stirred up) of water and fuel and then when that mixture was all
pushed through, it cleared up and ran normal. Leaving no sign of what had
happened.

Lessons learned, 1) do not fly VFR Over the Top unless you absolutely have to
and if you do get a lot of altitude so you might have a chance to glide to a
clear area to land and 2) really work the wings and sump the tanks vigorously
after rain or even dense fog - or for that matter anytime before you go flying
- you might have trapped water in the wing somewhere.

Thanks again to everybody who responded. I have learned a lot through this
experience.

Paul
Mooney M20F

On Sat, 18 Dec 2004 04:48:39 GMT, (Paul
Smedshammer) wrote:

In article , (Paul Smedshammer) wrote:
In article 05mvd.4322$lZ6.4235@trnddc02, wrote:


I made a step bank turn to stay under the fog ahead and I'm thinking there was
some water trapped behind a rib in the wing.

Paul,

Did they check to be sure the drain holes in the rib were not blocked by
sealant?


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

In article , Ron Rosenfeld wrote:

I made a step bank turn to stay under the fog ahead and I'm thinking there was

some water trapped behind a rib in the wing.

Paul,

Did they check to be sure the drain holes in the rib were not blocked by
sealant?


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

They inspected the wing tank that I was on when this occurred. Everything
looked okay. I'm sure we will go through it in more detail during the full
annual in the Spring. Thanks again to everybody. There is a huge wealth of
knowledge in these groups and it really helps to educate everybody reading
them.

Thanks,

Paul (N3506X, 1967 Mooney M20F)

Paul Smedshammer wrote:

Lessons learned, 1) do not fly VFR Over the Top unless you absolutely have to
and if you do get a lot of altitude so you might have a chance to glide to a
clear area to land and 2) really work the wings and sump the tanks vigorously
after rain or even dense fog - or for that matter anytime before you go flying
- you might have trapped water in the wing somewhere.

You didn't mention: (since this is a Mooney) check or replace the o-rings in the
fuel filler caps frequently, perhaps twice as often as required by the AD. Also
check for corrosion of the cap mechanism preventing the o-rings from sealing
properly.

Dave Butler wrote in
news:1103570747.387686@sj-nntpcache-5:

You didn't mention: (since this is a Mooney) check or replace the
o-rings in the fuel filler caps frequently, perhaps twice as often as
required by the AD. Also check for corrosion of the cap mechanism
preventing the o-rings from sealing properly.

Just prior to the rainy season this year I replaced all four o-rings. One
big one around the cap and the little one in the middle of the cap shaft.
You could really see the old ones were very stiff and brittle. I hear you
should replace these a couple of times a year. I think they only cost
about $8 for all four and I put them on myself in about 10 minutes.