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Lousy Idle

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dean.psiropoulos(at)veriz
Guest

Posted: Wed Dec 31, 2008 12:43 pm Post subject: Lousy Idle

Anyone have a few words of wisdom for me:



I'm pulling my hair out over a crappy engine idle that I can't seem to tame.

The basic problem is that I'll start the engine and it fires right up and

runs at about 700-750 RPM just like the book says it should.  But from

there, all it seems to want to do is gradually idle slower and slower as the

engine warms up until it barely runs (between 450-500 RPM) by the time I've

done all my checks and am ready to take the runway for takeoff.  

The engine is a new Mattituck built TMX-IO360 Lycoming clone with Lightspeed

electronic ignition on one side and a magneto on the other.  It also has

Airflow Performance fuel injection with purge valve, a Sterba wood prop and

Mark Landoll's 11 pound steel inertia ring bolted to the flywheel.  The

configuration is updraft with the AFP fuel controller bolted to the bottom

of the sump (like carbureted engines) and uses Van's airbox.  I've read the

AFP manual and talked to the tech there and adjusted the idle mixture and

stop numerous times but I can't seem to stabilize it.  When I have the

cowling off, I make the adjustments and taxi around a bit to warm up the

engine and it seems to be ok.  Then I'll put the cowling back on and the

symptoms seem to reappear.  There isn't anything banging against the cowling

that I can see that would be causing trouble so I'm totally stumped!



Anyone else having this problem? I'm flying out of a long but narrow strip

with trees on three sides and no good places to land near the airport.

Needless to say it makes me nervous, even though the engine runs strong just

off idle and at full power.  Thanks.



Dean Psiropoulos

RV-6A N197DM

4.1 hours

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rambud(at)windstream.net
Guest

Posted: Wed Dec 31, 2008 1:17 pm Post subject: Lousy Idle

I am no expert by any means, and I would not claim to have all of the

answers. I had a somewhat similar problem in an old C-35 Bonanza that had

spent a lot of time in the AZ desert. The engine started great, ran

beautifully and we never had a problem with it when we flew. The problem

ALWAYS occurred after landing and roll-out. We would bring the throttle back

to idle and the engine would die. We tweaked the fuel pressure until it was

at the stop. Same thing. During the annual we finally discovered the

culprit: the fuel line from the aux tank (in the baggage compartment) to the

engine was filled with sand (remember it came from the desert).



You may want to check your fuel lines for some possible contaminant. While I

am sure you don't have any sand, you may find you have something that takes

time to travel through the system to cause your problem.



Alternatively, you say that it runs fine with the cowling off but you have

the same problem when you put the cowling back on. Perhaps there is some

sort of blockage in your induction system between the cowling (air filter)

and the airbox?



I know these things sound simple and you most likely have looked into them,

but in the event you have not, sometimes it is the most simple of things

that creates our problems.



Bud



--

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GrummanDude

Joined: 15 Jan 2006
Posts: 926
Location: Auburn, CA

Posted: Wed Dec 31, 2008 1:43 pm Post subject: Lousy Idle

Call Ken Tunnell at LyCon

(559) 651-1070

Sent from my iPhone

On Dec 31, 2008, at 12:42 PM, "DEAN PSIROPOULOS" <dean.psiropoulos(at)verizon.net 

 > wrote:

 	  Quote: 	

 >

 Anyone have a few words of wisdom for me:

 I'm pulling my hair out over a crappy engine idle that I can't seem  

 to tame.

 The basic problem is that I'll start the engine and it fires right  

 up and

 runs at about 700-750 RPM just like the book says it should.  But from

 there, all it seems to want to do is gradually idle slower and  

 slower as the

 engine warms up until it barely runs (between 450-500 RPM) by the  

 time I've

 done all my checks and am ready to take the runway for takeoff.

 The engine is a new Mattituck built TMX-IO360 Lycoming clone with  

 Lightspeed

 electronic ignition on one side and a magneto on the other.  It also  

 has

 Airflow Performance fuel injection with purge valve, a Sterba wood  

 prop and

 Mark Landoll's 11 pound steel inertia ring bolted to the flywheel.   

 The

 configuration is updraft with the AFP fuel controller bolted to the  

 bottom

 of the sump (like carbureted engines) and uses Van's airbox.  I've  

 read the

 AFP manual and talked to the tech there and adjusted the idle  

 mixture and

 stop numerous times but I can't seem to stabilize it.  When I have the

 cowling off, I make the adjustments and taxi around a bit to warm up  

 the

 engine and it seems to be ok.  Then I'll put the cowling back on and  

 the

 symptoms seem to reappear.  There isn't anything banging against the  

 cowling

 that I can see that would be causing trouble so I'm totally stumped!

 Anyone else having this problem? I'm flying out of a long but narrow  

 strip

 with trees on three sides and no good places to land near the airport.

 Needless to say it makes me nervous, even though the engine runs  

 strong just

 off idle and at full power.  Thanks.

 Dean Psiropoulos

 RV-6A N197DM

 4.1 hours

- The Matronics Engines-List Email Forum -

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_________________
Gary
AuCountry Aviation
Home of Team Grumman

Kelly McMullen

Joined: 16 Apr 2008
Posts: 1188
Location: Sun Lakes AZ

Posted: Wed Dec 31, 2008 4:37 pm Post subject: Lousy Idle

Look for an intake manifold leak. Also, are you certain all plugs are good? Do you have an engine analyzer? If so, look for a cold cylinder, one not running close to the other 3 on EGT or CHT. See how it idles on just the magneto, or just the Lightspeed.

 

On Wed, Dec 31, 2008 at 1:42 PM, DEAN PSIROPOULOS <dean.psiropoulos(at)verizon.net (dean.psiropoulos(at)verizon.net)> wrote:

[quote] --> Engines-List message posted by: "DEAN PSIROPOULOS" <dean.psiropoulos(at)verizon.net (dean.psiropoulos(at)verizon.net)>

 

 Anyone have a few words of wisdom for me:

 

 I'm pulling my hair out over a crappy engine idle that I can't seem to tame.

 The basic problem is that I'll start the engine and it fires right up and

 runs at about 700-750 RPM just like the book says it should.  But from

 there, all it seems to want to do is gradually idle slower and slower as the

 engine warms up until it barely runs (between 450-500 RPM) by the time I've

 done all my checks and am ready to take the runway for takeoff.

 

 

 The engine is a new Mattituck built TMX-IO360 Lycoming clone with Lightspeed

 electronic ignition on one side and a magneto on the other.  It also has

 Airflow Performance fuel injection with purge valve, a Sterba wood prop and

 Mark Landoll's 11 pound steel inertia ring bolted to the flywheel.  The

 configuration is updraft with the AFP fuel controller bolted to the bottom

 of the sump (like carbureted engines) and uses Van's airbox.  I've read the

 AFP manual and talked to the tech there and adjusted the idle mixture and

 stop numerous times but I can't seem to stabilize it.  When I have the

 cowling off, I make the adjustments and taxi around a bit to warm up the

 engine and it seems to be ok.  Then I'll put the cowling back on and the

 symptoms seem to reappear.  There isn't anything banging against the cowling

 that I can see that would be causing trouble so I'm totally stumped!

 

 Anyone else having this problem? I'm flying out of a long but narrow strip

 with trees on three sides and no good places to land near the airport.

 Needless to say it makes me nervous, even though the engine runs strong just

 off idle and at full power.  Thanks.

 

 Dean Psiropoulos

 RV-6A N197DM

 4.1 hours

 

 

 

 

 

 

 

 [b]

- The Matronics Engines-List Email Forum -

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_________________
Kelly McMullen
A&P/IA, EAA Tech Counselor
KCHD

azevedoflyer(at)gmail.com
Guest

Posted: Sat Jan 03, 2009 5:16 pm Post subject: Lousy Idle

Dean,

 Have you notice any symptons of engine running richer and richer as the idle slows down?

 Like brown smoke coming out of exhaust?

 If you have a paper air filter, try without it. I've seen some paper filters clog up under higher temps.

 Cheers,

 Miguel Azevedo

 N8714D

 PA22/20-150

 On Wed, Dec 31, 2008 at 3:42 PM, DEAN PSIROPOULOS <dean.psiropoulos(at)verizon.net (dean.psiropoulos(at)verizon.net)> wrote:

 [quote]--> Engines-List message posted by: "DEAN PSIROPOULOS" <dean.psiropoulos(at)verizon.net (dean.psiropoulos(at)verizon.net)>

 

Anyone have a few words of wisdom for me:



I'm pulling my hair out over a crappy engine idle that I can't seem to tame.

The basic problem is that I'll start the engine and it fires right up and

 runs at about 700-750 RPM just like the book says it should.  But from

there, all it seems to want to do is gradually idle slower and slower as the

engine warms up until it barely runs (between 450-500 RPM) by the time I've

 done all my checks and am ready to take the runway for takeoff.

The engine is a new Mattituck built TMX-IO360 Lycoming clone with Lightspeed

electronic ignition on one side and a magneto on the other.  It also has

 Airflow Performance fuel injection with purge valve, a Sterba wood prop and

Mark Landoll's 11 pound steel inertia ring bolted to the flywheel.  The

configuration is updraft with the AFP fuel controller bolted to the bottom

 of the sump (like carbureted engines) and uses Van's airbox.  I've read the

AFP manual and talked to the tech there and adjusted the idle mixture and

stop numerous times but I can't seem to stabilize it.  When I have the

 cowling off, I make the adjustments and taxi around a bit to warm up the

engine and it seems to be ok.  Then I'll put the cowling back on and the

symptoms seem to reappear.  There isn't anything banging against the cowling

 that I can see that would be causing trouble so I'm totally stumped!



Anyone else having this problem? I'm flying out of a long but narrow strip

with trees on three sides and no good places to land near the airport.

  [quote][b]

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Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?Engines-List

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