Matronics Email Lists :: View topic

Matronics Email Lists
Web Forum Interface to the Matronics Email Lists

Get Email Distribution Too! FAQ Search Memberlist Usergroups Register

Profile Log in to check your private messages Log in

Mixture & fuel flow

Matronics Email Lists Forum Index -> RV-List

View previous topic :: View next topic

Author Message

n616tb(at)btsapps.com
Guest

Posted: Tue Oct 10, 2006 9:09 am Post subject: Mixture & fuel flow

Hi Listers



I now have about 12 hours on my Aero Sport engine and starting to think

about leaning it. (The instructions indicate to run it rich)  My fuel flow

shows about 14 GPH with it full rich at 8500 feet.  When I lean it I have to

pull the mixture back about 3/4 of the way to get it down to 10 GPH.  This

seems excessive to me.  I did not lean to a stumble at this point.  Also, my

VM-1000 has a leaning process but I don't understand it yet.  Plus I have a

cylinder #3 that is running about 425 that concerns me.



Is it possible the carburetor needs to be altered or adjusted somehow?



Thanks

Tim

- The Matronics RV-List Email Forum -

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?RV-List

ronlee(at)pcisys.net
Guest

Posted: Tue Oct 10, 2006 10:04 am Post subject: Mixture & fuel flow

 	  Quote: 	
		  I now have about 12 hours on my Aero Sport engine and starting to think

about leaning it. (The instructions indicate to run it rich)  My fuel flow

shows about 14 GPH with it full rich at 8500 feet.  When I lean it I have to

pull the mixture back about 3/4 of the way to get it down to 10 GPH.  This

seems excessive to me.  I did not lean to a stumble at this point.  Also, my

VM-1000 has a leaning process but I don't understand it yet.  Plus I have a

cylinder #3 that is running about 425 that concerns me.


	


I can't tell if anything you mentioned suggest the need for adjustments of

the carb or your cooling system but 14 GPH at 8500' is too rich.  I don't 

spend

much time that low (8500') but 10 GPH there may be ok.  I usually lean to

stumble then enrichen until smooth...and sometimes one more mixture notch.



Are you saying that pulling the mixture out 3/4 of the way is excessive or

10GPH is excessive?   Have you checked the flow after leaning to engine

stumble/running rough then mixture in until smooth?



At my flight altitudes (above 11,500') I am 7.5 GPH or less.



Ron Lee

- The Matronics RV-List Email Forum -

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?RV-List

n616tb(at)btsapps.com
Guest

Posted: Tue Oct 10, 2006 10:14 am Post subject: Mixture & fuel flow

Hi Ron,



My thought is that pulling the mixture 3/4 of the way just to get from 14

down to 10 is a lot.  I will try to lean till it stumbles next time, but am

cautious of getting to lean while the engine is new.



Really the question might be is 14 pretty high for full rich mixture at that

altitude?  On the ground it shows nearly 17 GPH full rich. (3200' field)  I

would like to see closer to 8 GPH when leaned. (0-360-A1A)



I suppose my fuel flow meter could be off.



Tim



[quote] --

- The Matronics RV-List Email Forum -

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?RV-List

ronlee(at)pcisys.net
Guest

Posted: Tue Oct 10, 2006 11:54 am Post subject: Mixture & fuel flow

 	  Quote: 	
		  My thought is that pulling the mixture 3/4 of the way just to get from 14

down to 10 is a lot.  I will try to lean till it stumbles next time, but am

cautious of getting to lean while the engine is new.


	


I start my engine with the mixture 1/2 way out from full rich then soon

leaner about 1/4" for taxi.  Verify correct mixture at run-up (field elevation

6800')



 	  Quote: 	
		  Really the question might be is 14 pretty high for full rich mixture at that

altitude?  On the ground it shows nearly 17 GPH full rich. (3200' field)  I

would like to see closer to 8 GPH when leaned. (0-360-A1A)


	


Why would you be full rich at 8500'?  A better question would be what do

others get when leaned properly including CHT and maybe EGT.



 	  Quote: 	
		  I suppose my fuel flow meter could be off.


	


If it can be calibrated then that is possible.  Have you verified fuel 

remaining

per your instrumentation versus actual.  If those are off then the number of

pulses per unit fuel needs to be adjusted.  That will affect your fuel flow.



Obviously follow engine maker instructions for break-in and call them if you

have questions about limits of EGT, CHT, etc



Ron Lee

- The Matronics RV-List Email Forum -

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?RV-List

ronlee(at)pcisys.net
Guest

Posted: Tue Oct 10, 2006 1:45 pm Post subject: Mixture & fuel flow

 	  Quote: 	
		  Really the question might be is 14 pretty high for full rich mixture at that

altitude?  On the ground it shows nearly 17 GPH full rich. (3200' field)  I

would like to see closer to 8 GPH when leaned. (0-360-A1A)


	


I was near sea level last week and the highest I saw during climb was in

the 12-14 GPH range.    May have been 12 or 13.  Just don't recall.



O-360, FP



Ron Lee

- The Matronics RV-List Email Forum -

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?RV-List

dbris200(at)sbcglobal.net
Guest

Posted: Tue Oct 10, 2006 7:14 pm Post subject: Mixture & fuel flow

Tim,

 

 The hot #3 cylinder can usually be cured by making sure that the rear baffle is spaced about 1/8" from the rear of the cylinder. If the baffle is too tight, there isn't enough airflow around the rear of the cylinder.

 

 Dave

 

 

 Tim Bryan wrote:

 [quote]    	  Quote: 	
		  --> RV-List message posted by: "Tim Bryan" <n616tb(at)btsapps.com> (n616tb(at)btsapps.com)

Hi Listers



I now have about 12 hours on my Aero Sport engine and starting to think

about leaning it. (The instructions indicate to run it rich)  My fuel flow

shows about 14 GPH with it full rich at 8500 feet.  When I lean it I have to

pull the mixture back about 3/4 of the way to get it down to 10 GPH.  This

seems excessive to me.  I did not lean to a stumble at this point.  Also, my

VM-1000 has a leaning process but I don't understand it yet.  Plus I have a

cylinder #3 that is running about 425 that concerns me.



Is it possible the carburetor needs to be altered or adjusted somehow?



Thanks

Tim



  	
 [b]

- The Matronics RV-List Email Forum -

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?RV-List

Gary.A.Sobek

Joined: 09 Jan 2006
Posts: 217
Location: SoCAL USA

Posted: Wed Oct 11, 2006 12:10 am Post subject: Mixture & fuel flow

There should be something in the archives about fuel flow reading higher 

with the boost pump on.  I see 17 GPH fuel flow full power takeoff with the 

boost pump on near sea level.



The mixture control on my carb come out very far in normal cruise at any 

altitude.  It is at least 1/2 way or more out at most cruise altitudes.



It will take many tanks of gas to get the fuel flow constant adjusted to a 

value you like.  Early on numbers and not very meaningful.



The fuel transducer is 2.5% accurate. You should be able to adjust the 

constant it uses to get that close at ONE and only one power setting.



I record all fuel used in my airplane in a spreadsheet and reset the fuel 

totalizer every fill.  I only check the constant once a year now and it sits 

right at 3.5% more fuel used than what I purchase over the course of a year. 

  Yes I could adjust it more to get closer but I like the idea of having 

more fuel than what my instruments tell me.



Gary A. Sobek

"My Sanity" RV-6 N157GS O-320 Hartzell,

1,956 + Flying Hours So. CA, USA

- The Matronics RV-List Email Forum -

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?RV-List

romott(at)adelphia.net
Guest

Posted: Wed Oct 11, 2006 4:31 am Post subject: Mixture & fuel flow

I suggest you read the three excellent  articles on the left side of this web page:

  

 http://www.advancedpilot.com/assist.html

  

 These will give you lots of good information about  leaning (and properly operating) your engine.  These techniques work best  with fuel injected engines, but are also applicable to carbureted  engines.

  

 Ronnie Brown

 N713MR - Velocity Elite RG

  

  

   [quote][b]

- The Matronics RV-List Email Forum -

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?RV-List

DOUGPFLYRV(at)aol.com
Guest

Posted: Wed Oct 11, 2006 11:42 am Post subject: Mixture & fuel flow

Any ideas for a hot #4 cyl?

 Thanks,

 D. Preston

  [quote][b]

- The Matronics RV-List Email Forum -

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?RV-List

Display posts from previous:

	Matronics Email Lists Forum Index -> RV-List	All times are GMT - 8 Hours
Page 1 of 1

Jump to:

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum