engine startup problem

Hi -

Very rarely, one of the 6-cylinder Lycoming IO-540's in my Aztec acts
up after startup. There is a fair amount of vibration, and a high MP
(20") for the resting 1000rpm, and if the engine monitor is turned on,
it shows three of the six cylinder (1, 3, 6) not making any heat.
Turning on the electric boost pump, playing with the magnetos,
mixture, throttle, all seem to not help.

After a shutdown and a minute's rest, a subsequent startup is usually
perfect, with all cylinders firing well throughout the runup and
flight. Post-flight visual inspection of the cylinders appears
normal.

Does this set of signs ring a bell toward a possible explanation?

- FChE

Perhaps the injectors are plugging.

Frank,
I thought about this a while. The best I can come up with is one mag is
mis-firing and your cyl 5/6 engine monitor sensors are reversed. Have
you checked the impulse coupling on the magneto(s)?
Michelle

Frank Ch. Eigler wrote:

Hi -

Very rarely, one of the 6-cylinder Lycoming IO-540's in my Aztec acts
up after startup. There is a fair amount of vibration, and a high MP
(20") for the resting 1000rpm, and if the engine monitor is turned on,
it shows three of the six cylinder (1, 3, 6) not making any heat.
Turning on the electric boost pump, playing with the magnetos,
mixture, throttle, all seem to not help.

After a shutdown and a minute's rest, a subsequent startup is usually
perfect, with all cylinders firing well throughout the runup and
flight. Post-flight visual inspection of the cylinders appears
normal.

Does this set of signs ring a bell toward a possible explanation?

- FChE

I was thinking along the same lines Michelle was. Are your mags shower of
sparks type? Could it be that your mags need timing? It sounds like
"something" doesn't work when it's cold, and refuses to work until it's re
started and warm. Impulse coupling was my first guess, but on our Aztec's
Bendix S-200's have shower of sparks, so I'm thinking maybe it could be your
shower of sparks vibrator for one mag.

Jim

"Michelle P" wrote in message
ink.net...
Frank,
I thought about this a while. The best I can come up with is one mag is
mis-firing and your cyl 5/6 engine monitor sensors are reversed. Have
you checked the impulse coupling on the magneto(s)?
Michelle

Frank Ch. Eigler wrote:

Hi -

Very rarely, one of the 6-cylinder Lycoming IO-540's in my Aztec acts
up after startup. There is a fair amount of vibration, and a high MP
(20") for the resting 1000rpm, and if the engine monitor is turned on,
it shows three of the six cylinder (1, 3, 6) not making any heat.
Turning on the electric boost pump, playing with the magnetos,
mixture, throttle, all seem to not help.

After a shutdown and a minute's rest, a subsequent startup is usually
perfect, with all cylinders firing well throughout the runup and
flight. Post-flight visual inspection of the cylinders appears
normal.

Does this set of signs ring a bell toward a possible explanation?

- FChE

http://www.aeroelectric.com/articles/sos_v3.pdf

Is a wiring dia. for shower of sparks type install.
Jim

"Jim Burns" wrote in message
...
I was thinking along the same lines Michelle was. Are your mags shower of
sparks type? Could it be that your mags need timing? It sounds like
"something" doesn't work when it's cold, and refuses to work until it's re
started and warm. Impulse coupling was my first guess, but on our Aztec's
Bendix S-200's have shower of sparks, so I'm thinking maybe it could be
your
shower of sparks vibrator for one mag.

Jim

"Michelle P" wrote in message
ink.net...
Frank,
I thought about this a while. The best I can come up with is one mag is
mis-firing and your cyl 5/6 engine monitor sensors are reversed. Have
you checked the impulse coupling on the magneto(s)?
Michelle

Frank Ch. Eigler wrote:

Hi -

Very rarely, one of the 6-cylinder Lycoming IO-540's in my Aztec acts
up after startup. There is a fair amount of vibration, and a high MP
(20") for the resting 1000rpm, and if the engine monitor is turned on,
it shows three of the six cylinder (1, 3, 6) not making any heat.
Turning on the electric boost pump, playing with the magnetos,
mixture, throttle, all seem to not help.

After a shutdown and a minute's rest, a subsequent startup is usually
perfect, with all cylinders firing well throughout the runup and
flight. Post-flight visual inspection of the cylinders appears
normal.

Does this set of signs ring a bell toward a possible explanation?

- FChE

Hi -


Michelle P wrote:

I thought about this a while. The best I can come up with is one mag
is mis-firing and your cyl 5/6 engine monitor sensors are
reversed. Have you checked the impulse coupling on the magneto(s)?

As Jim indicated, the magnetos are shower-of-sparks type. I wonder if
the magnetos are exonerated by the fact that this is an after-start
situation (so the starting portions may not be relevant), and that the
condition persisted with each magneto alone.

Thanks to others for the suggestions of injector clogging and the
infamous Lycoming sticky valve "morning sickness". I hope it's not
the latter.


- FChE

It is Morning Sickness... Sticking exhaust valves from carbon deposits
and lead salts - a Lycoming special... A mag being off timing is not
going to drop the manifold pressure to 20 inches at part throttle, but
3 valves stuck open to the great outdoors will, in a heartbeat...
After you shut down and let it sit the heat build up in the heads
expands the valve bore and they finally start "poppeting" again...

Try putting AVBLEND in the oil and add MMO to the gas (4 ounces per ten
gallons) and take it out and fly it right away.. GIve it a good long
run at high power settings... WIth a bit of luck this will begin
dissolving the lead and carbon deposits in the valve guide and you are
home free... If it persists then you need to pull the valve cover(s),
alternately squirt CARB CLEANER and WD-40 (or Liquid Wrench and LPS #2)
etc., down the exhaust valve stem and immediately bounce the heck out
of the valve(s) with a wood block and a ball peen hammer.... Don't be
shy, make sure the piston is at the bottom of it's travel, and whack
the heck out of the valve, make it really dance ( I normally remove the
rocker arm to do this so I can put some muscle into it, but you can
leave the rocker arm on)... Chanting in tongues while you whack away
is highly recommended for the theraputic value...

denny

I have found KROIL dissolves carbon build ups much quicker than WD-40.
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1000 East Thompson Lane
P.O. Box 110098
Nashville, Tennessee 37222-0098
www.kanolabs.com
800-311-3374

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"Clay" writes:

I have found KROIL dissolves carbon build ups much quicker than WD-40.
KREEN is even faster than KROIL.
Kano Labs
1000 East Thompson Lane
P.O. Box 110098
Nashville, Tennessee 37222-0098
www.kanolabs.com
800-311-3374


BTW:
Anyone who thinks WD-40 is penetrating oil must also think
a screwdriver is something made with vodka. Kroil *is*
the REAL penetrating oil.....

But boy does it stink...
--
A host is a host from coast to
& no one will talk to a host that's close........[v].(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433

Kroil *is*
the REAL penetrating oil.....

Is it better than Mouse Milk?

Dan