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912ULS Mag Drop

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John Hauck

Joined: 09 Jan 2006
Posts: 4639
Location: Titus, Alabama (hauck's holler)

Posted: Wed Jan 30, 2008 6:55 pm Post subject: 912ULS Mag Drop

Gang:



My idea of why the mag was dropping was correct.



After oiling the throttle clevis's, changing spark plugs, with no 

improvement, I played with the enricher at 4000 rpm while performing the mag 

check.  Indication was lean condition at 4000 rpm.



Today, despite the wind and cold, I got the needles raised a notch, which 

puts the clip in the bottom groove of the fuel needles.  It worked.  Now I 

am a happy camper once again.



Proves not all 912 engines are created equal.  I never encountered this 

problem with my last 912ULS.



Didn't get to test fly because it was getting late by the time I finished 

up.



These new generation Bing carbs are much easier to get to the top innards of 

the carb to get at the fuel needles.  The older ones were a little more work 

intensive.



Always feels good to get those little problems solved.



john h

mkIII

_________________
John Hauck
MKIII/912ULS
hauck's holler
Titus, Alabama

lucien

Joined: 03 Jun 2007
Posts: 721
Location: santa fe, NM

Posted: Thu Jan 31, 2008 6:37 am Post subject: Re: 912ULS Mag Drop

 	  John Hauck wrote: 	
		  Gang:



My idea of why the mag was dropping was correct.



After oiling the throttle clevis's, changing spark plugs, with no 

improvement, I played with the enricher at 4000 rpm while performing the mag 

check.  Indication was lean condition at 4000 rpm.



Today, despite the wind and cold, I got the needles raised a notch, which 

puts the clip in the bottom groove of the fuel needles.  It worked.  Now I 

am a happy camper once again.



Proves not all 912 engines are created equal.  I never encountered this 

problem with my last 912ULS.



Didn't get to test fly because it was getting late by the time I finished 

up.



These new generation Bing carbs are much easier to get to the top innards of 

the carb to get at the fuel needles.  The older ones were a little more work 

intensive.



Always feels good to get those little problems solved.



john h

mkIII 	




Sounds to me more like just some variation in the carbs rather than an engine difference?

I've encountered the same thing with the bings on my 2-strokes. Same jetting and atmospheric conditions, but still slightly different resulting mixtures from motor to motor. I just adjusted them as needed....



The bings on the 912 seem to work really well. The plane originally lived at 1500' MSL and now lives at 7000' MSL; all I had to do was put the vent lines into the air filters and lean out the idle mix about 1/2 turn to get a proper looking plug.... 



BTW, the enrichener is a great debugging tool like you said - I used it to diagnose a carp-in-carb problem after a recent fuel line change. Saves a lot of time and head-scratching 



LS

_________________
LS
Titan II SS

JetPilot

Joined: 10 Jan 2006
Posts: 1246

Posted: Thu Jan 31, 2008 9:36 am Post subject: Re: 912ULS Mag Drop

Lucien,



How did you run the vent lines into the Air Filters.  Can you post some pictures of that ?   I have one vent that is spitting out some fuel, and I would rather not have it going all over the engine.



Anyone seen what causes a vent line on the 912-s to spit some fuel, its not much, I cant see it, but its enough to discolor and leave a gooey discoloration where it hits the cylinder.



Mike

_________________
"NO FEAR" - If you have no fear you did not go as fast as you could have !!!

Kolb MK-III Xtra, 912-S

lucien

Joined: 03 Jun 2007
Posts: 721
Location: santa fe, NM

Posted: Thu Jan 31, 2008 9:47 am Post subject: Re: 912ULS Mag Drop

 	  JetPilot wrote: 	
		  Lucien,



How did you run the vent lines into the Air Filters.  Can you post some pictures of that ?   I have one vent that is spitting out some fuel, and I would rather not have it going all over the engine.



Anyone seen what causes a vent line on the 912-s to spit some fuel, its not much, I cant see it, but its enough to discolor and leave a gooey discoloration where it hits the cylinder.



Mike 	




I'll try to get some pics of what I did ASAP. I used some brass barbs from Lowes to make the fittings, the type used to splice tubing. Barbs on each end with a small ridge in the center. I then drilled holes in the back of the air cleaners, cleaned out the debris and pushed the fitting in up to the ridge. I also smeared a little silicone adhesive to help hold it and seal up any possible leaks. Then pushed the vent lines onto the exposed barb.



This leaned out the top end to where it was supposed to be even as high as 10,000' MSL, it was running a little rich at full throttle before that.



If you're getting fuel spitting out of the vents, you probably have something plugged up in the carburettor somewhere or it's possible the carb is running over.



My 2-stroke Bings would sometimes spit fuel out of the vents if they were running over or needed cleaning.



The outside of the carburettor should be totally dry as should the vents......



LS

_________________
LS
Titan II SS

slyck(at)frontiernet.net
Guest

Posted: Thu Jan 31, 2008 10:06 am Post subject: 912ULS Mag Drop

How did the carp get in the fuel line?  Amazing!

bb

do not archive

On 31, Jan 2008, at 9:37 AM, lucien wrote:



 	  Quote: 	
		   

 John Hauck wrote:

> Gang:

>

> My idea of why the mag was dropping was correct.

>

> After oiling the throttle clevis's, changing spark plugs, with no

> improvement, I played with the enricher at 4000 rpm while  

> performing the mag

> check.  Indication was lean condition at 4000 rpm.

>

> Today, despite the wind and cold, I got the needles raised a  

> notch, which

> puts the clip in the bottom groove of the fuel needles.  It  

> worked.  Now I

> am a happy camper once again.

>

> Proves not all 912 engines are created equal.  I never encountered  

> this

> problem with my last 912ULS.

>

> Didn't get to test fly because it was getting late by the time I  

> finished

> up.

>

> These new generation Bing carbs are much easier to get to the top  

> innards of

> the carb to get at the fuel needles.  The older ones were a little  

> more work

> intensive.

>

> Always feels good to get those little problems solved.

>

> john h

> mkIII

 Sounds to me more like just some variation in the carbs rather than  

 an engine difference?

 I've encountered the same thing with the bings on my 2-strokes.  

 Same jetting and atmospheric conditions, but still slightly  

 different resulting mixtures from motor to motor. I just adjusted  

 them as needed....



 The bings on the 912 seem to work really well. The plane originally  

 lived at 1500' MSL and now lives at 7000' MSL; all I had to do was  

 put the vent lines into the air filters and lean out the idle mix  

 about 1/2 turn to get a proper looking plug....



 BTW, the enrichener is a great debugging tool like you said - I  

 used it to diagnose a carp-in-carb problem after a recent fuel line  

 change. Saves a lot of time and head-scratching 



 LS



 --------

 LS

 FS II





 Read this topic online here:



 http://forums.matronics.com/viewtopic.php?p=161543#161543

John Hauck

Joined: 09 Jan 2006
Posts: 4639
Location: Titus, Alabama (hauck's holler)

Posted: Thu Jan 31, 2008 10:42 am Post subject: 912ULS Mag Drop

> If you're getting fuel spitting out of the vents, you probably have 

something plugged up in the carburettor somewhere or it's possible the carb 

is running over.

 	  Quote: 	
		  

 My 2-stroke Bings would sometimes spit fuel out of the vents if they were 

 running over or needed cleaning.



 The outside of the carburettor should be totally dry as should the 

 vents......



 LS


	


Lucien:



Probably that carb plugging up the works and causing the carbs to spit fuel. 





john h

mklIII

_________________
John Hauck
MKIII/912ULS
hauck's holler
Titus, Alabama

John Hauck

Joined: 09 Jan 2006
Posts: 4639
Location: Titus, Alabama (hauck's holler)

Posted: Thu Jan 31, 2008 10:44 am Post subject: 912ULS Mag Drop

 	  Quote: 	
		    I have one vent that is spitting out some fuel, and I would rather not 

 have it going all over the engine.



 Anyone seen what causes a vent line on the 912-s to spit some fuel, its 

 not much, I cant see it, but its enough to discolor and leave a gooey 

 discoloration where it hits the cylinder.



 Mike


	




Mike B:



You probably have a fuel vapor stand off problem, rather than a float 

chamber static port blowing fuel on your engine.



All engines, two and four stroke, have a little cloud of fuel vapor that 

stands off the intake of the carb.  I don't know why gasoline engines do 

this, but they do, from a 2 hp B&S to my old 85 hp Ford Flat Head V8.  These 

I can vouch for because, as a kid, I experimented with them.



Rotax two strokes are set up to  blow the fuel vapor stand off out the air 

filter because they are oriented perpendicular to the air stream.



If you are running conical air filters, they are more supceptible to blowing 

the fuel vapor off the mouth of the carb and onto your engine since it is a 

pusher and the aircleaner is sitting right out there in the front of the 

engine.  Sometimes the flat cake pan K&N air filters will cure the problem, 

but in my case, a pair of air filter covers did the job nicely.  I also 

route the float chamber static tube into the cover between it and the air 

filter so it will read the same satic pressure as the static port on the lip 

of the carb.



Take care,



john h

mkIII

_________________
John Hauck
MKIII/912ULS
hauck's holler
Titus, Alabama

John Hauck

Joined: 09 Jan 2006
Posts: 4639
Location: Titus, Alabama (hauck's holler)

Posted: Thu Jan 31, 2008 11:00 am Post subject: 912ULS Mag Drop

>> BTW, the enrichener is a great debugging tool like you said - I

 	  Quote: 	
		  > used it to diagnose a carp-in-carb problem after a recent fuel line 

> change. Saves a lot of time and head-scratching 

>

> LS


	




BB/Gang:



Yea, how did the carp get in there?  If he won't plug up a carb, nothing 

will.



john h

mkIII

_________________
John Hauck
MKIII/912ULS
hauck's holler
Titus, Alabama

John Hauck

Joined: 09 Jan 2006
Posts: 4639
Location: Titus, Alabama (hauck's holler)

Posted: Thu Jan 31, 2008 11:24 am Post subject: 912ULS Mag Drop

> Probably that carb plugging up the works and causing the carbs to spit 

fuel.

 	  Quote: 	
		   


	


Gang:



Blew that one, didn't I.   Misspelled "carp".  Drat'it.



john h

mkIII

_________________
John Hauck
MKIII/912ULS
hauck's holler
Titus, Alabama

lucien

Joined: 03 Jun 2007
Posts: 721
Location: santa fe, NM

Posted: Thu Jan 31, 2008 3:17 pm Post subject: Re: 912ULS Mag Drop

 	  John Hauck wrote: 	
		  >> BTW, the enrichener is a great debugging tool like you said - I

 	  Quote: 	
		  > used it to diagnose a carp-in-carb problem after a recent fuel line 

> change. Saves a lot of time and head-scratching 

>

> LS

BB/Gang:

Yea, how did the carp get in there?  If he won't plug up a carb, nothing 

will.

john h

mkIII 	

Oops, sorry about the carp.... no fish involved but "crap" for sure......

That's where I learned to finally sand down the sharp edges on any barbed fittings during a fuel line change... and to thoroughly flush the new assemblies before installation and otherwise be operating-room clean when messing with fuel lines......

LS

_________________
LS
Titan II SS

gaman(at)att.net
Guest

Posted: Fri Feb 01, 2008 5:51 am Post subject: 912ULS Mag Drop

I imagine any kind of fish in your carburetor could be a problem!



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