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Float Level

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cffd(at)pgrb.com
Guest

Posted: Sun Apr 27, 2008 2:43 pm Post subject: Float Level

My EGT's at WOT are a little high 1250 F, while the  cruise is a little rich 1200 F.  

 Jabiriu 2200, serial # 988, solid lifters, Bing  40mm carb, no tuning kit, main jet 255, needle jet 276.

 Does anyone know how much the WOT  EGT's would go down by raising the float 1/32"? 

 Then I can lower the needle to lean  cruise.

 Chuck D.

   [quote][b]

Lynn Matteson

Joined: 10 Jan 2006
Posts: 2778
Location: Grass Lake, Michigan

Posted: Sun Apr 27, 2008 3:47 pm Post subject: Float Level

The Bing manual for the carb says NOT to change the float (from what  

they suggest) to cure a problem, but to cure the problem by  

addressing either the main, the needle jet or the jet needle,  

whichever "neighborhood" the problem resides in (my analogy). I've  

read of guys who have adjusted the float height, but Bing says not  

to. Are you sure you have a "lowerable needle"? Mine is not, having  

only one groove for the snap ring.



Lynn Matteson

Grass Lake, Michigan

Kitfox IV Speedster  w/Jabiru 2200

flying w/490+ hrs

On Apr 27, 2008, at 6:39 PM, Chuck Deiterich wrote:



 	  Quote: 	
		   My EGT's at WOT are a little high 1250 F, while the cruise is a  

 little rich 1200 F.

 Jabiriu 2200, serial # 988, solid lifters, Bing 40mm carb, no  

 tuning kit, main jet 255, needle jet 276.

 Does anyone know how much the WOT EGT's would go down by raising  

 the float 1/32"?

 Then I can lower the needle to lean cruise.

 Chuck D.

 forums.matronics.com_- 

 ============================================================ _- 

 contribution_- 

 ============================================================

_________________
Lynn
Kitfox IV-Jabiru 2200
N369LM

cffd(at)pgrb.com
Guest

Posted: Mon Apr 28, 2008 6:18 am Post subject: Float Level

Lynn,



I am sure I have a needle with several grooves.

When I replaced the float needle with one that has a stronger built in 

spring (black), I did not readjust the float.  The spring in the old needle 

(orange) would compress at 1.5 Oz, while the spring in new needle takes 31 

Oz to compress (yes 20 times more).  This means that any compression of the 

weaker spring would effectively have a higher float level.  Thus my float 

may be a bit low.  The 255 main is larger than what Jabiru now puts in the 

Bing.  SB 18-1 says mine came with a 250 but it did not, as the main jet 

size is scribed in the side of the carb body and on the jet itself.  Lately 

they are using a 245 main jet.  Needle jet sizes can be misleading as the 

needles used are different.



Chuck D.

 	  Quote: 	
		  

 Time: 04:47:22 PM PST US

 From: Lynn Matteson <lynnmatt(at)jps.net>

 Subject: Re: Float Level

 The Bing manual for the carb says NOT to change the float (from what

 they suggest) to cure a problem, but to cure the problem by

 addressing either the main, the needle jet or the jet needle,

 whichever "neighborhood" the problem resides in (my analogy). I've

 read of guys who have adjusted the float height, but Bing says not

 to. Are you sure you have a "lowerable needle"? Mine is not, having

 only one groove for the snap ring.

andy(at)suncoastjabiru.co
Guest

Posted: Mon Apr 28, 2008 9:06 am Post subject: Float Level

Chuck,



You did the right thing to change the float needle for the stronger (spring)

one as it gives a better seating. However, I would follow Jabiru's advice

NOT to try adjusting the mixture with the float level. You might get away

with it, but our advice was always to change mixture settings on the

pre-economy tuning by raising or lowering the jet needle for fine

adjustment, and if this wasn't enough, change the needle jet for a bigger

one and reset the needle to the 'standard' position which is groove #2, or

one-up from the bottom. If the Wide-Open-Throttle (WOT) setting was too

rich, you could go to a smaller main-jet size but as others have said here,

the relationship between the needle shape and resulting jet orifices (?)

meant that in practice, you could actually remove the main jet completely

and there would be no real difference in WOT mixture, because the fuel still

has to get past the needle jet, which at most throttle/slide positions,

controlled the mixture. The economy tuning definitely improved the cruise

and WOT mixture relationships with a new needle shape, so they went for just

jet-changing rather than (also) needle height adjustment for mixture

alteration. This is why the 'older' straight-tapered needles have 4 grooves

for adjustment, but the new economy needles only have one. The guy who

developed the new needle shape told me he'd prefer the new setup to be

called 'more tunable' rather than 'economy' as it is the needle that

provides the right relationship now between cruise (relatively lean) and WOT

(relatively rich). Unfortunately, the new setup got off to a poor start as

they'd not allowed for the over-lean conditions present in the carb /

induction when operating in lower temperatures, hence with experience the

successive guidance to go bigger on jets to richen the whole range, but

particularly cruise.



You may also be unaware that Jabiru went through a phase a few years back of

drilling-out jets to achieve the required mixture, so what was stamped on

the jet wasn't necessarily the size of the hole.....This was from memory on

2200s before the year 2000, or so, but ask your dealer as they have factory

information (I'm afraid I don't at present). To compound the issues, my

understanding is that the sizes stamped on main jets don't correspond to the

jet diameter, but on needle jets they do! This means a 2.80 needle jet has a

2.80mm hole, but I'm pretty sure a 255 main jet isn't 2.55mm. I have no clue

why this is.



Andy 



--

tjs22t(at)verizon.net
Guest

Posted: Mon Apr 28, 2008 11:20 am Post subject: Float Level

 	  Quote: 	
		   To compound the issues, my

 understanding is that the sizes stamped on main jets don't correspond to 

 the

 jet diameter, but on needle jets they do! This means a 2.80 needle jet has 

 a

 2.80mm hole, but I'm pretty sure a 255 main jet isn't 2.55mm. I have no 

 clue

 why this is.


	


Andy,



Nor do I, but I can verify that what you say about "older" jets being 

drilled out is true.  On my #051 3300 both the needle jet and the main jet 

had been drilled out and were not close to what was stamped on them.



I took to using my set of # drills to figure out what I had before 

experimenting.  Really would have been nice to know that from the factory. 

Jabiru seem to be blind to many common sense pieces of info their customers 

deserve.



cheers  jeff

ronal22(at)verizon.net
Guest

Posted: Mon Apr 28, 2008 1:25 pm Post subject: Float Level

My understanding is that any EGT temp. 1400 F or  below is fine with the Jabiru 2200 engine.  I was getting temps up to 1500,  so I changed the needle jet from 276 to 280 and the main jet from 220 to  240.  Now my high temp in cruise is 1375 with the OAT  65 F or  above.  My engine is Ser. No. 2030.

 Ron Smith

 Kitfox 4 with Jabiru  2200

    [quote][b]

Lynn Matteson

Joined: 10 Jan 2006
Posts: 2778
Location: Grass Lake, Michigan

Posted: Tue Apr 29, 2008 11:55 am Post subject: Float Level

Chuck-

It must be that since your engine and mine, they changed their  

thinking on jet needles, and sent mine with only one groove.

I have all three float needles, and I concur with your reading of 1.5  

oz on the "silver-springed" light needle. My "gold-springed" medium  

needle scales at between 4-5 oz, and my "black-springed" high needle  

is in the plane at this time, so I defer to your reading of 31 oz.  

The silver, gold, and black colors are what I observed, and are not  

"official" by Bing. They refer to the three needles as "float needle  

light" , "float needle medium", and "float needle heavy." I ended up  

with all three due to various fartings around with the carb. I'm  

pretty sure the number of my main (#220) conforms to the size etched  

on the carb, but as Andy said earlier.....

"You may also be unaware that Jabiru went through a phase a few years  

back of

drilling-out jets to achieve the required mixture, so what was  

stamped on

the jet wasn't necessarily the size of the hole.....This was from  

memory on

2200s before the year 2000, or so, but ask your dealer as they have  

factory

information (I'm afraid I don't at present). To compound the issues, my

understanding is that the sizes stamped on main jets don't correspond  

to the

jet diameter, but on needle jets they do! This means a 2.80 needle  

jet has a

2.80mm hole, but I'm pretty sure a 255 main jet isn't 2.55mm. I have  

no clue

why this is."

....that number may or may not be of value.

Lynn Matteson

Grass Lake, Michigan

Kitfox IV Speedster  w/Jabiru 2200

flying w/490+ hrs

On Apr 28, 2008, at 10:15 AM, Chuck Deiterich wrote:

 	  Quote: 	

 <cffd(at)pgrb.com>

 Lynn,

 I am sure I have a needle with several grooves.

 When I replaced the float needle with one that has a stronger built  

 in spring (black), I did not readjust the float.  The spring in the  

 old needle (orange) would compress at 1.5 Oz, while the spring in  

 new needle takes 31 Oz to compress (yes 20 times more).  This means  

 that any compression of the weaker spring would effectively have a  

 higher float level.  Thus my float may be a bit low.  The 255 main  

 is larger than what Jabiru now puts in the Bing.  SB 18-1 says mine  

 came with a 250 but it did not, as the main jet size is scribed in  

 the side of the carb body and on the jet itself.  Lately they are  

 using a 245 main jet.  Needle jet sizes can be misleading as the  

 needles used are different.

 Chuck D.

>

> Time: 04:47:22 PM PST US

> From: Lynn Matteson <lynnmatt(at)jps.net>

> Subject: Re: Float Level

> The Bing manual for the carb says NOT to change the float (from what

> they suggest) to cure a problem, but to cure the problem by

> addressing either the main, the needle jet or the jet needle,

> whichever "neighborhood" the problem resides in (my analogy). I've

> read of guys who have adjusted the float height, but Bing says not

> to. Are you sure you have a "lowerable needle"? Mine is not, having

> only one groove for the snap ring.

>

_________________
Lynn
Kitfox IV-Jabiru 2200
N369LM

Lynn Matteson

Joined: 10 Jan 2006
Posts: 2778
Location: Grass Lake, Michigan

Posted: Sun May 04, 2008 3:11 am Post subject: Float Level

Ron-

Did you happen to measure (with a # drill) the 240 main before you  

installed it? Or for that matter the 220? I measured my 220 and it  

is .078".  I'm thinking of drilling my 220 out, as it seems to be the  

reason that my EGT's are still up in the 1400's when I've gone to a  

larger needle jet (twice) and it didn't lower the EGT's.



Lynn



On Apr 28, 2008, at 5:19 PM, RONAL SMITH wrote:



 	  Quote: 	
		   My understanding is that any EGT temp. 1400 F or below is fine with  

 the Jabiru 2200 engine.  I was getting temps up to 1500, so I  

 changed the needle jet from 276 to 280 and the main jet from 220 to  

 240.  Now my high temp in cruise is 1375 with the OAT  65 F or  

 above.  My engine is Ser. No. 2030.

 Ron Smith

 Kitfox 4 with Jabiru 2200

 forums.matronics.com_- 

 ============================================================ _- 

 contribution_- 

 ============================================================

_________________
Lynn
Kitfox IV-Jabiru 2200
N369LM

d.goddard(at)ns.sympatico
Guest

Posted: Sun May 04, 2008 4:39 am Post subject: Float Level

Hi Lynn. I'm not trying to come across "all expert" but we tried simply 

drilling a larger hole in mains years ago with Mikuni carbs on motorcycles 

and the results were unpredictable. It might be better to simply buy a 

larger main jet from Bing if you feel the need. I've heard you can do it 

with flow testing but I figured it wasn't worth the effort.

---

Lynn Matteson

Joined: 10 Jan 2006
Posts: 2778
Location: Grass Lake, Michigan

Posted: Sun May 04, 2008 2:25 pm Post subject: Float Level

Thanks for the input, Dave.

I too, was a little wary when I heard folks talk about drilling jets  

out, thinking it would be better to buy them and know that the  

precision would be better. I've got a metal lathe, and had good  

success in drilling my 2.76 needle jet out to a #33 drill size... 

0.113". This didn't change my EGT's any (leading me to think the main  

needed to be larger) but today I did something else. I was having  

trouble getting one of my EGT's below the 1400° F range, and the left  

bank was always the hottest. Well today I decided to rotate the carb  

as per the suggested manner....top towards the cool side. I had done  

this before, but when I recently added air-straightening vanes inside  

my air duct (attaches directly to carb) I made sure the carb was  

rotated directly vertical. I had flown it for a week or so that way,  

and today I decided to try rotating it again. I am quite pleased to  

say that this time it worked, and I now have 3 cylinders within about  

30 degrees of one another, and one (#3) that is about 70 degrees  

colder. I'm ready to live with that, I think. I no longer see the 1400 

+ reading on cyl #4, like I had before. Knowing me, I'll probably try  

to tweak the rotation a bit and see if #3 and #4 can be brought a bit  

closer together.



It was interesting to note that during previous operation at around  

2850 rpm, straight and level, my EIS would alarm showing high EGT  

spread of over 212° F. I had arbitrarily set this number into the EIS  

unit some time ago. Now I don't get that alarm, or see such a large  

spread. I wish I could figure a way to precisely control the position  

of the carb when rotating it, or doing the rotation from the cabin,  

but that's asking for too much. : )



So for the time being, I won't be drilling my main out, or do any  

other jet tweaking. I'll just concentrate on trying to fine-tune the  

position of the carb.



Maybe what is needed is a cockpit-controlled splitter that will allow  

for diverting the mixture toward the hottest cylinder/bank. It  

wouldn't need to be much...just a lever-controlled vane positioned in  

front of the built-in splitter. This is getting a bit radical, and  

I'm hoping that persons with better testing facilities than I (read:  

the Jabiru engineers) could do some work on the carb and come up with  

a closer cylinder-to-cylinder match of EGT's.

Lynn Matteson

Grass Lake, Michigan

Kitfox IV Speedster  w/Jabiru 2200

flying w/503+ hrs



On May 4, 2008, at 8:20 AM, Dave G. wrote:



[quote] 

 <d.goddard(at)ns.sympatico.ca>



 Hi Lynn. I'm not trying to come across "all expert" but we tried  

 simply drilling a larger hole in mains years ago with Mikuni carbs  

 on motorcycles and the results were unpredictable. It might be  

 better to simply buy a larger main jet from Bing if you feel the  

 need. I've heard you can do it with flow testing but I figured it  

 wasn't worth the effort.

 ---

_________________
Lynn
Kitfox IV-Jabiru 2200
N369LM

ronal22(at)verizon.net
Guest

Posted: Wed May 07, 2008 1:49 pm Post subject: Float Level

Lynn,

 I didn't measure the 240 main jet before I put it  in, but here are measurements for the 220 main jet - .078", drill no.  47,

 and for the spare 245 main jet - .089", drill no.  43.  You could extrapolate between these two numbers to get a size for the  240 main jet.  I would error on the smaller size, otherwise you could be  running rich.  Hope this helps.

 Ron Smith, KF IV with Jabiru 2200A  engine.

    [quote][b]

gelco(at)npgcable.com
Guest

Posted: Wed May 07, 2008 3:44 pm Post subject: Float Level

please remove Gaylord Clark from jabiru engine  list. GC

 [quote]   ---

Lynn Matteson

Joined: 10 Jan 2006
Posts: 2778
Location: Grass Lake, Michigan

Posted: Thu May 08, 2008 7:12 am Post subject: Float Level

Thanks, Ron. At the present, I'm pretty happy with the 220, but  

warmer ambient temps might have me going larger on the main jet, so  

this is valuable info.



Lynn

On May 7, 2008, at 5:45 PM, RONAL SMITH wrote:



 	  Quote: 	
		   Lynn,

 I didn't measure the 240 main jet before I put it in, but here are  

 measurements for the 220 main jet - .078", drill no. 47,

 and for the spare 245 main jet - .089", drill no. 43.  You could  

 extrapolate between these two numbers to get a size for the 240  

 main jet.  I would error on the smaller size, otherwise you could  

 be running rich.  Hope this helps.

 Ron Smith, KF IV with Jabiru 2200A engine.

 forums.matronics.com_- 

 ============================================================ _- 

 contribution_- 

 ============================================================

_________________
Lynn
Kitfox IV-Jabiru 2200
N369LM

skypics

Joined: 12 May 2008
Posts: 2

Posted: Tue May 13, 2008 7:34 am Post subject: Re: Float Level

Main is 255 and a bit too lean change to 260



Needle is 2.76 and a bit too rich change to 2.70



My Jab 2200 is hyd lifter type with 225 main drilled out to a 235 and climb on the hottest is 1280 F



My needle jet was supposed to be a 2.80, but when Jabiru drilled it they didn't drill far enough and that left a ridge at the bottom of the hole that was equivalent to a 2.75.  This gave 1425-1450 on the hottest in cruise. 



I drilled it the rest of the way with a #33 drill to clean out the ridge.  This gave a 2.80 and the hot EGT in cruise is 1400 F.



John M

_________________
John

pennington(at)gainusa.com
Guest

Posted: Tue May 13, 2008 9:19 am Post subject: Float Level

Hello everyone.



I will be building another airplane using the Jabiru 3300 engine. Has anyone 

had problems with reliability?



Thanks

Gary



---

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