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Kolb/Jabiru carb overflow
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Thom Riddle

Joined: 10 Jan 2006
Posts: 1597
Location: Buffalo, NY, USA (9G0)

Posted: Thu Jan 13, 2011 5:41 am Post subject: Re: Kolb/Jabiru carb overflow

Chris,



Thanks for the update about two different springs. That was news to me and very much worth knowing. I've not taken my fuel pump apart but will next condition inspection just to see what is what. 



I hope you will post this information on the JabiruEngines Yahoo group since that seems to be the busiest of the Jabiru lists.

_________________
Thom Riddle
Buffalo, NY (9G0)

Don't worry about old age... it doesn't last very long.
- Anonymous

mdnanwelch7(at)hotmail.co
Guest

Posted: Thu Jan 13, 2011 6:36 am Post subject: Kolb/Jabiru carb overflow

Chris,

 

  In viewing the photos of the inside of your fuel pump, it appears to

me that you have a significant amount of water getting into your fuel

system.  Either by condensation, fuel container transfer, or something,

it looks like an issue you should address.

 

  I don't recall seeing anywhere how many hours you have on your 

engine, but it can't be a tremendous amount.  I'm just wondering how

an area that is supposed to have zero (!!) moisture, is somehow getting

so much.  Maybe I'm not seeing the photos clearly, but that's what I see.

 

  In my opinion, if your fuel system is well designed, and you don't have any 

"obvious" culprits, at the very least I'd consider using a 'water separator'

style funnel.  I'm not a fuel expert, or anything like that, but it just seems 

to me there is something you need to fix!!

 

  I'm curious......do you fill up your fuel tank(s) in your plane EVERY time

you park it?   According to what I heard once, you are supposed to fill up

your tanks after you fly the plane.  Full tanks have very little room for air

to deposit moisture on the inside walls of your fuel tank.

 

  Do you have a 'well placed' moisture trap??  I mean, one that does a great

job of letting ALL the water settle into it, and allows for easy and thorough

drainage.  I think this is something you REALLY need to be confident of!!

Let's keep the off-airport landings to a minimum!

  

 Mike Welch



 



  		 	   		    [quote][b]

John Hauck

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

Posted: Thu Jan 13, 2011 6:54 am Post subject: Kolb/Jabiru carb overflow

In viewing the photos of the inside of your fuel pump, it appears to

me that you have a significant amount of water getting into your fuel

system.



Mike Welch

Mike W/Gang:



The corrosion seems to be on the crank case side of the pump, not the fuel 

side.



The engine oil is probably not getting hot enough to cook off condensation, 

which collects where ever it can find a home, e.g., the cavity in the fuel 

pump and many other places inside the engine.



I do not know about the Jabiru, but 912 engine oil must get at least 190F, 

during a flight, to be hot enough to burn off condensation.  An easy check 

is remove the oil tank cap, after a flight, to see if there is a milky 

substance covering the bottom of the cap.  If it is, it isn't running hot 

enough.



For me, that much corrosion in the fuel pump would be cause to wonder about 

the rest of the engine.



Chris has been flying in some very cold weather this year.



john h

mkIII

Titus, Alabama

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

jbhart(at)onlyinternet.ne
Guest

Posted: Thu Jan 13, 2011 7:47 am Post subject: Kolb/Jabiru carb overflow

From: Mike Welch <mdnanwelch7(at)hotmail.com>

Date: Thu, 13 Jan 2011 06:26:37 -0800

 	  Quote: 	

  In viewing the photos of the inside of your fuel pump, it appears to

me that you have a significant amount of water getting into your fuel

system.  Either by condensation, fuel container transfer, or something,

it looks like an issue you should address.

 	  Quote: 	

Mike,

Every engine has combustion blow-by from the combustion chamber that passes 

the rings and piston and on into the crankcase.  And, since a high 

percentage of the combustion products is water vapor, it is not surprising 

to find it accumulating and condensing on things inside the crankcase.  In 

most cases, if you can keep the crankcase and the parts in side it at or 

above 180 degrees F, most of the moisture will not condense inside the case 

and will blow on out the vent as vapor.  Fortunately for us two strokers 

this is not much of problem as the crankcase is constantly purged with fresh 

air, fuel, and lubricant.

Jack B. Hart FF004

Winchester, IN

ces308

Joined: 03 Nov 2008
Posts: 317
Location: houghton lake ,mi

Posted: Thu Jan 13, 2011 7:50 am Post subject: Re: Kolb/Jabiru carb overflow

Mike and John,hello,



The fuel pump is on the side of the engine,right in the slipstream and hangs upside down and tilted...it looks like oil for lubrication comes from just enough clearance around the push-rod to drip on the pump actuator and then a small ,about an 1/8 " hole at the bottom for an oil return to the crank case...there is a cavity above that where the return spring is that has no air going through it or oil getting to it,so with the slipstream of cold air going over the hot/warm pump case it has to be making some moisture there....I don't think it's a lot ,but enough to collect on the spring and the bottom of the diaphragm.I have never seen moisture in the oil fill tube or the dipstick...Oil temps in the winter...at 16* is 160-185...I have never found any water in my fuel system...



I'll get a picture of where the pump goes on so you can see what I'm talking about...



chris ambrose

M3X/Jabiru  A-2200   172. hrs TT

N327CS

mdnanwelch7(at)hotmail.co
Guest

Posted: Thu Jan 13, 2011 8:40 am Post subject: Kolb/Jabiru carb overflow

 	  Quote: 	
		   The corrosion seems to be on the crank case side of the pump, not the fuel 

 side.

 Chris has been flying in some very cold weather this year.

 

 john h

 mkIII

 Titus, Alabama


	


John, guys,

 

  Thanks for the clarification.  You can see I'm no Jabiru fuel pump expert

Thom Riddle

Joined: 10 Jan 2006
Posts: 1597
Location: Buffalo, NY, USA (9G0)

Posted: Thu Jan 13, 2011 8:59 am Post subject: Re: Kolb/Jabiru carb overflow

Attached is a photo of the Jabiru 2200 fuel pump from the Installation Manual.

jab2200 fuel pump.jpg

Description:

Filesize:

296.45 KB

Viewed:

8803 Time(s)

_________________
Thom Riddle
Buffalo, NY (9G0)

Don't worry about old age... it doesn't last very long.
- Anonymous

John Hauck

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

Posted: Thu Jan 13, 2011 9:27 am Post subject: Kolb/Jabiru carb overflow

Thanks for the clarification.  You can see I'm no Jabiru fuel pump 

expert.

One thing I do know, tho, is that simply reaching 180-190 degrees F isn't

all there is to moisture in your crankcase.



Mike Welch

Mike W/Folks:



I went back and looked at the new Owners Manual, 912 series engines:



- Eng Oil Temp operating range 190 to 230F (This temp is read at the outlet 

end of the oil pump, but before it goes back through the engine.  This is 

oil fresh from the oil cooler.)



- The manual also states eng oil temp should attain at least 212F some time 

during flight each day.  It does not explain if this is 212F at the eng oil 

temp sender on the aft end of the oil pump, or oil temp when blow by gases 

push the oil out the crankcase on its way to the oil tank after it has been 

heated inside the engine.



My experience has worked out well using the old spec which was attain 190F 

during the flight.  No time at or above that temp specified.  If I comply 

with this, I have a nice clean oil tank cap on the inside.  If I don't get 

the eng oil to 190F (indicated), I'll have the tale tell milky looking oil 

residue inside the cap.



My experience has also been that condensation converts to steam well below 

the boiling point of 212F.  I also know there is 3 to 5 psi crankcase 

pressure constantly purging the crankcase of steam/contaminents, pushing oil 

out of the crankcase and back to the oil tank.  The condensation does not 

have to be boiled out of the crankcase.



About the only way one could get the engine oil temp to 190F on the ground 

(912) would be bypass the eng oil cooler and tape up the radiator. 

Difficult to get 120F, as required, prior to going full throttle, especially 

when it is cold.



Don't think it is the cooling down that causes condensation in the 912 

engines, but the by product of combustion.  There is a lot of water in the 

air, especially here in the SE.



john h

mkIII

Titus, Alabama

_________________
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 13, 2011 9:29 am Post subject: Kolb/Jabiru carb overflow

Attached is a photo of the Jabiru 2200 fuel pump from the Installation 

Manual. You can't see it in this photo but the fuel line FROM the pump to 

the carb is behind the supply line with the fire sleeve to the pump.



--------

Thom Riddle

Thom R/Folks:



The way the pump is mounted, inverted and canted, seems to be a built in 

situation to trap condensation.



The 912 eng driven fuel pump is a "run of the mill" Pierburg pump, about the 

same as used on the old Opels.  It is a throwaway pump that can not be 

disassembled.  It is mounted on the gearbox and driven off a lobe on the 

prop shaft.  Maybe this location reduces the amount of condensation it is 

exposed to, maybe not.  



john h

mkIII

Titus, Alabama

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

Thom Riddle

Joined: 10 Jan 2006
Posts: 1597
Location: Buffalo, NY, USA (9G0)

Posted: Thu Jan 13, 2011 9:55 am Post subject: Re: Kolb/Jabiru carb overflow

My Jabiru engine has its fuel pump located as shown in the photo I posted. I have an oil breather "catch can" that I empty after each flight by opening the petcock in the catch can drain line. It always drains out several drops of muddy/wet looking oil/water muck. This air/oil separator must be catching most, if not all, of the moisture in the oil system because the oil dip stick never shows any signs of this excrement or condensation, nor is there any when I change the oil. 



On my pusher configuration, with the engine hanging out in the breeze, and me living in the north with mild summers, it does not need an oil cooler and therefore does not have one installed. I rarely if ever fly in winter so the oil temps always manage to get up to the 170F minimum (at return line to engine) specified by Jabiru, as long as I don't baby the engine during climb.  I doubt seriously, that the oil temp would get up to minimum in this weather without closing down some of the air scoop, but I could be wrong, since the CHTs get up to normal in cold weather. 



18F currently (Thursday 1PM) and still snowing... almost continuously since Tuesday around noon. Beautiful to behold, if you are dressed properly.

_________________
Thom Riddle
Buffalo, NY (9G0)

Don't worry about old age... it doesn't last very long.
- Anonymous

by0ung(at)brigham.net
Guest

Posted: Thu Jan 13, 2011 12:40 pm Post subject: Kolb/Jabiru carb overflow

the crankcase is probably doing ok...  if the  fuel pump is out in the open like the fuel pump on the 912,,,   it  will have a lot more cooling air around it,,,  and even if the crankcase is  200 deg c   the fuel pump may stay 160   or so..    remember there is very little movement of oil or gases inside the fuel  pump..  it is sepperated from the case with a gasket.  all which limit  the heat saturation into the pump.

  

 boyd

  

 <<<<<<<<<<<<<<<<<<

 

  Seeing as how the moisture is a product of Chris's crankcase  (and not his fuel

delivery system), then this would possibly be a  characteristic of his flying conditions,

or flying habits, wouldn't  it?   Possibly due to the cold, northern climate, or the duration  

of his flights, or maybe even the wrong thermostat for his conditions,  clearly something 

needs to be remedied.

 

  Without a doubt,  Chris needs to make his flights a lot longer, or certainly long

enough to  achieve a dryer moisture level inside his engine's crankcase.....'cause what  he

has at the present is causing some risky landings!!

 

   Simple question, Chris;   How long would you say your typical flight  is?  15 minutes?

30??   Also, can you get a higher temp rated  thermostat?  This might help a lot.

 

Mike Welch



[quote]

[b]

Thom Riddle

Joined: 10 Jan 2006
Posts: 1597
Location: Buffalo, NY, USA (9G0)

Posted: Thu Jan 13, 2011 1:47 pm Post subject: Re: Kolb/Jabiru carb overflow

Mike,



Jabiru engines are entirely air-cooled therefore there is no thermostat to change. I always climb hard after take-off to get the temps up, even climb higher than I really want to go, if necessary for just this purpose. The air/oil separator also does a good job of getting rid of most of the moisture.

_________________
Thom Riddle
Buffalo, NY (9G0)

Don't worry about old age... it doesn't last very long.
- Anonymous

mdnanwelch7(at)hotmail.co
Guest

Posted: Thu Jan 13, 2011 2:44 pm Post subject: Kolb/Jabiru carb overflow

> Jabiru engines are entirely air-cooled therefore there is no thermostat to change. > --------

 	  Quote: 	
		   Thom Riddle


	


  

  Thom & Chris, and all other Jabiru drivers,

  

   I forgot the air-cooled part.......doh!!       In that case, the the answer is

 simple!!  You guys need to fly your planes more!!  

  

   Evidently the old adage;  TIME SPENT FLYING IS NOT DEDUCTED FROM

ONE'S LIFE!!  , has a corollary;  TIME SPENT FLYING YOUR JABIRU ENGINE

IS GOOD FOR IT, IN FACT, THE MORE THE BETTER!

  

 : )

  

 Mike Welch

  

 		 	   		    [quote][b]

by0ung(at)brigham.net
Guest

Posted: Thu Jan 13, 2011 2:48 pm Post subject: Kolb/Jabiru carb overflow

the crankcase is probably doing ok...  if the  fuel pump is out in the open like the fuel pump on the 912,,,   it  will have a lot more cooling air around it,,,  and even if the crankcase is  200 deg c   the fuel pump may stay 160   or so..    remember there is very little movement of oil or gases inside the fuel  pump..  it is sepperated from the case with a gasket.  all which limit  the heat saturation into the pump.

  

 boyd

  

 >>>>>>>>>>>>.

  

 ment to say   200 deg F   not  c

  

 do not archive

  

  

 ive made my mistake for the year,,, best pay more  attention the rest of the year!!!!!

  



   [quote][b]

ces308

Joined: 03 Nov 2008
Posts: 317
Location: houghton lake ,mi

Posted: Fri Jan 14, 2011 10:25 pm Post subject: Re: Kolb/Jabiru carb overflow

Hello all..



Here is an update on the fuel pump delema...last Saturday we eliminated the mechanical pump all together and flew it on just the electric pump at 2- lbs of pressure and flew it for 20 minutes and all was fine...ok..then it was suggested we cut  some of the spring off and that would lower the pressure...we did and it did...ran it for about 6 minutes and all was good...I talked to Jim from Jabiru in CA ,told him what we did and he said if it worked to leave it alone,try it,if it works ,fly it....ok...I tested it  and it was fine...then I flew it...it was good for just over 6 minutes,then it started flooding out again...it did keep running allbeit not very good and I made a safy landing...when I got to the hangar I placed the pressure guage back on and it went right to 7+ lbs...why??   



Here is what I think happened...Saturday we cut off the spring ,started it up and the pressure went to 2-3 lbs...It only ran for  a few minutes...

 

Today,after Jim said if it works ,check it and fly it....

 

I checked it,ran it for 6 minutes and it seemed ok...it got to about 3.2 # and seemed to be steady ...

 

then I flew it for just over 6 minutes and then it started flooding again...

 

What I think is happening is when we cut it off it just took longer for the fuel to build up pressure and once everything was full of gas,the spring was still working and although it wasn't going up as far, when it did push up,it was still pushing at 7# psi...we only shortened the spring...not relieve any tension......do you see what I mean???  does it make any sense???  I hope so...cause I'm going nutts !!!!   LOL



Frank is sending me his NEW silver spring which is supposed to be 2-3 lbs...if that does not work I will put a regulator on and set it to 2-3 lbs..

Again..Thank you Frank ! 



chris ambrose

M3X/Jabiru A-2200  172.0hrs

N327CS

aoldman(at)xtra.co.nz
Guest

Posted: Sat Jan 15, 2011 1:56 am Post subject: Kolb/Jabiru carb overflow

ARE YOUR TANKS VENTING CORRECTLY?

captainron1(at)cox.net
Guest

Posted: Sat Jan 15, 2011 3:56 am Post subject: Kolb/Jabiru carb overflow

Is there supposed to be a fuel return line or something like that, that may be plugged up? I am trying to remember from the Mikuni iirc on the Cuyana I flew last year. But it had a pulse pump and very little pressure I guess. Why is yours flooding is not making any sense. 



It may not be flooding at all. and in fact it may be too lean. I would check and make sure there are no cracks in the fuel lines. I had to put down the Pterodactyl on my maiden flight next to a MacDonald restaurant because of a crack in the fuel primer pump nipple. It displayed the symptoms of too rich, poor throttle response and chocking at full throttle, and it progressively got worse till I could not maintain altitude.

Check all of your lines for cracks anything from the fuel tank to the Carb.

John Hauck

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

Posted: Sat Jan 15, 2011 6:23 am Post subject: Kolb/Jabiru carb overflow

I hope so...cause I'm going nutts !!!!   LOL



 chris ambrose



Chris A/Folks:



If it was mine, I would have already replaced the fuel pump with a new 

serviceable pump.  Not worth the chance of getting hurt and/or ruining your 

airplane being a test pilot.



How much does a new pump cost?



Of course, as I age I am not nearly as bold as I used to be.  



john h

mkIII

hauck's holler

Titus, Alabama

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

jbhart(at)onlyinternet.ne
Guest

Posted: Sat Jan 15, 2011 7:09 am Post subject: Kolb/Jabiru carb overflow

At 10:25 PM 1/14/11 -0800, you wrote:

 	  Quote: 	
		  



Hello all..

..........................>
	


 	  Quote: 	
		   

What I think is happening is when we cut it off it just took longer for the 

fuel to build up pressure and once everything was full of gas,the spring was 
	


still working and although it wasn't going up as far, when it did push up,it 

was still pushing at 7# psi...we only shortened the spring...not relieve any 

tension......do you see what I mean???  does it make any sense???  I hope 

so...cause I'm going nutts !!!!   LOL

 	  Quote: 	
		  


	


Chris,



The force (F) exerted by the fuel pump spring is equal to the change in 

spring length (L) times the spring constant (K).  Or F = L x K.  L is 

predetermined by the cam lobe in the engine.  The spring constant is 

determined by type of material and diameter of the spring wire.



So you are correct when you do not see any change due to cutting the spring. 

 You did not change the pump stroke or the wire spring constant.  The only 

way to reduce pump stroke (L) is to add gasket material to the point that 

the cam follower does not remain in contact with the cam.  The only other 

option is to replace the spring with one that is the same physical size but 

wound from smaller diameter wire thereby reducing the spring constant (K).



If your new silver spring does not do the job, and pressure remains too 

high, purchase a new spring that is close to the same length and outside 

diameter, but with smaller diameter wire.  Springs can be purchased over the 

web and in some cases from your local hardware store.



Jack B. Hart FF004

Winchester, IN

frank.goodnight(at)att.ne
Guest

Posted: Sat Jan 15, 2011 7:49 am Post subject: Kolb/Jabiru carb overflow

Hi , never having seen your fuel pump or the spring that controls the presure , i'd like to hazzard

 a guess. Hopefully if I' wrong some of the more knoweledgabe folks on  the the list can correct

 me before any damage is done. I have always thought that if a spring was made shorter (cut ) that

 would make the spring stiffer ---easy to check, just cut an old spring and see what happens---.

 Looks to me like that would raise the fuel presure, could be you need a longer (stretched ?)sprnig

 or one with thiner wire.

 Frank Goodnight 

  

  

  

 

   From: Jack B. Hart <jbhart(at)onlyinternet.net>

To: kolb-list(at)matronics.com

Sent: Sat, January 15, 2011 9:08:06 AM

Subject: Re: Re: Kolb/Jabiru carb overflow



--> Kolb-List message posted by: "Jack B. Hart" <jbhart(at)onlyinternet.net (jbhart(at)onlyinternet.net)>



At 10:25 PM 1/14/11 -0800, you wrote:

 	  Quote: 	
		  --> Kolb-List message posted by: "ces308" <ces308(at)ldaco.com (ces308(at)ldaco.com)>



Hello all..

..........................>
	


 	  Quote: 	
		   

What I think is happening is when we cut it off it just took longer for the 

fuel to build up pressure and once everything was full of gas,the  spring was 
	


still working and although it wasn't going up as far, when it did push up,it 

was still pushing at 7# psi...we only shortened the spring...not relieve any 

tension......do you see what I mean???  does it make any sense???  I hope 

so...cause I'm going nutts !!!!  LOL

 	  Quote: 	
		  


	


Chris,



The force (F) exerted by the fuel pump spring is equal to the change in 

spring length (L) times the spring constant (K).  Or F = L x K.  L is 

predetermined by the cam lobe in the engine.  The spring constant is 

determined by type of material and diameter of the spring wire.



So you are correct when you do not see any change due to cutting the spring. 

You did not change the pump stroke or the wire spring constant.  The only 

way to reduce pump stroke (L) is to add gasket material to the point that 

the cam follower does not remain in contact with the cam.  The only other  

option is to replace the spring with one that is the same physical size but 

wound from smaller diameter wire thereby reducing the spring constant (K).



If your new silver spring does not do the job, and pressure remains too 

high, purchase a new spring that is close to the same length and outside 

diameter, but with smaller diameter wire.  Springs can be purchased over the 

web and in some cases from your local hardware store.



Jack B. Hart FF004

Winchester, IN  

 [quote][b]

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