Rich running j2200?? Need help

Australian designed and manufactured Jabiru Aircraft/

Moderator: Moderators

Jakes
Pre-take off checks
Posts: 84
Joined: Mon Jun 04, 2007 3:21 pm
Closest Airfield: Louis Trichardt
Location: Louis Trichardt, Limpopo
Has liked: 0
Been liked: 0

Rich running j2200?? Need help

Unread post by Jakes » Fri Jun 15, 2018 7:46 pm

Good day all,
I own a Jabiru SP 470 with 2200 engine. When I bought my jabbi that I loooooooove, I did the 1000 hour top end overall and replaced with 4 new thin fin heads. I flew the jabbi for 40 hours since the top end and enjoyed every minute of it.......no temperature issues......nothing!!!!!! Flew the previous day with no issues for about an hour, I arrived at the airport and when I started her she was running rough. I pulled the choke and she was running smoother. After a while, pushed the choke back and she was idling very rough again and the revs dropped to 600rpm up to the point she wanted to die. When I pushed the revs up to 2000rpm and did a mag check she was running a bit better and the mag check were normal, but as soon as I pulled the throttle she was running rough again.......very low rpm's. This problem started overnight!!
I then checked the following:
1. I checked all the plug cables ......nothing wrong
2. I opened the distributors.........dry and clean.....both rotors in great condition.
3. I disconnected the scat tubing to carburator and started her up..........same problem.....no difference thus air wasnt a problem.
4. Since the first day I flew her....I have always checked the exhaust colour with my preflight.....always a dark grey colour....I only fly AVGAS......checked the exhausts and they were totally black and very rooty.....obviously she was suddenly running rich.
5. Checked the spark plugs and on all 4 cylinders they were the same black and rooty colour........confirming rich running.

My thinking.......in the last 4 hours of flying I realized that my fuel consumption got higher from 13 to 15 liters per hour to 17 liters per hour. She was obviously started to run rich. I think that it could be a carburator problem?

Please give me some advice or if somebody experienced something like this previously???
I have removed the carburator in the meantime and was thinking of opening it and see if there is an obvious problem.
Maybe a sticking floating level?
Is there still Bing 94 carburator kits available or parts? Where can I source parts or a service kit for the carburator?

Any help will be appreciated!!

Regards,
Jaco
Addicted to the smell of AVGAS!
User avatar
Marius Schrenk
Niner Tousand
Niner Tousand
Posts: 9891
Joined: Mon Oct 05, 2009 3:34 pm
Closest Airfield: 300m from home
Location: Inni skadu van n kameeldoringboom.
Has liked: 165 times
Been liked: 96 times

Re: Rich running j2200?? Need help

Unread post by Marius Schrenk » Sat Jun 16, 2018 7:34 am

Hi Jaco, carburetors do not change over night. If they do change it would be in the opposite direction....leaner from a build up. Check your air cleaner filter...and intake skate hoses.....do not change anything on the Bing. If you really want to clean it with carb cleaner....but not on the motor running....if you do that please replace your oil to get rid of the ammonia....which would eat your engine from inside .Pulling the choke and running smooth tells me its a alternate air source....look for a blockage in your outside air intake or a lose intake manifold/carb. How is your float level ? Are you switching of your electric fuel pump after take off ?
Politics attracts crooks and lawyers,most of the time its the same person.
Jakes
Pre-take off checks
Posts: 84
Joined: Mon Jun 04, 2007 3:21 pm
Closest Airfield: Louis Trichardt
Location: Louis Trichardt, Limpopo
Has liked: 0
Been liked: 0

Re: Rich running j2200?? Need help

Unread post by Jakes » Sat Jun 16, 2018 6:29 pm

Hi Marius,

Thank you so much for the reply.
I am also very reluctant to change anything on the carb. While its out, I can just as well clean it with carb cleaner outside.
I have disconnected the scat hose to test if its air related and without air from the aircleaner it did exactly the same.
I have once or twice forgot the fuelpump on after take off but it was only for 15 min or so.

Jaco.
Addicted to the smell of AVGAS!
Jakes
Pre-take off checks
Posts: 84
Joined: Mon Jun 04, 2007 3:21 pm
Closest Airfield: Louis Trichardt
Location: Louis Trichardt, Limpopo
Has liked: 0
Been liked: 0

Re: Rich running j2200?? Need help

Unread post by Jakes » Sat Jun 16, 2018 6:32 pm

Sorry Marius........I have checked the float level by putting the fuelpump on for a minute or two and closing the fuel selector. It was about 13mm from the top but I did feel some fuel on my hand when removing it.....so I would say.....more or less 12mm from the top of the bowl.
Addicted to the smell of AVGAS!
User avatar
Marius Schrenk
Niner Tousand
Niner Tousand
Posts: 9891
Joined: Mon Oct 05, 2009 3:34 pm
Closest Airfield: 300m from home
Location: Inni skadu van n kameeldoringboom.
Has liked: 165 times
Been liked: 96 times

Re: Rich running j2200?? Need help

Unread post by Marius Schrenk » Sat Jun 16, 2018 8:38 pm

I believe 11 to 13 mm is in the right ball park. Check your coil clearance to the flywheel.
Politics attracts crooks and lawyers,most of the time its the same person.
jcwCT
Priming
Posts: 37
Joined: Tue Apr 24, 2012 7:48 pm
Has liked: 0
Been liked: 0

Re: Rich running j2200?? Need help

Unread post by jcwCT » Sat Jun 16, 2018 9:36 pm

I would strongly suggest removing, disassembling, and inspecting your fuel pump.

I own a 2010 J230-SP (Australian kit assembled by Jabiru NA in Tennessee with 3300 hydraulic lifter engine). I bought it used in 2012 with 160 hrs. on the Hobbs. With winter mornings as cold as -15°C and summer afternoons as high as 38°C where I live and fly, keeping the fuel/air mixture and distribution where it needed and EGTs in range and sort of even was "challenging" (to put it nicely) but jet changes, adjustments, and a few needed repairs at different times yielded predictable results.

Eighteen months ago, with approximately 400 hrs. on the Hobbs, my A&P and I started chasing intermittent issues -- running too lean and high EGTs one moment, everything "in the green" the next, rough running at xyz RPMs one flight, engine running smooth as butter at the same RPMs the next flight, with unpredictable and counter intuitive results when we changed jets or adjustments. During our "chase," we rebuilt the carburetor, replaced all of the scat hoses, "rebuilt" the intake manifold/spider, installed a cobra head baffle to straighten the intake airflow etc., checked the actual fuel flow from the fuel pump, and more.

Last April the engine suddenly refused to run smoothly over 2,000 RPM a few minutes after takeoff, the electric backup fuel pump no help, and an emergency return to the airport, we pulled the main fuel pump. It was full oily, rusty, crap
Jabiru Fuel Pump 2.JPG
Jabiru Fuel Pump 1.JPG
Installed new fuel pump. All intermittent problems solved. EGTs more even and within range.
You do not have the required permissions to view the files attached to this post.
Jakes
Pre-take off checks
Posts: 84
Joined: Mon Jun 04, 2007 3:21 pm
Closest Airfield: Louis Trichardt
Location: Louis Trichardt, Limpopo
Has liked: 0
Been liked: 0

Re: Rich running j2200?? Need help

Unread post by Jakes » Sun Jun 17, 2018 4:33 pm

jcwCT,
Thank you so much for the reply.
I also tried and see if there was a difference if the fuel pump was on.....and the same results....didnt change the rough running.
jcw....I will most certainly check the fuelpump.....it just could be the problem. I will folllow your and Marius's advice and leave the carb alone...maybe just clean it nicely.
I will post the results of the fuelpump as soon as I check it out.
Jaco
Addicted to the smell of AVGAS!
User avatar
ZuluBen
Six Tousand
Six Tousand
Posts: 6593
Joined: Mon May 09, 2005 4:54 pm
Location: Gaborone, Botswana
Has liked: 6 times
Been liked: 3 times

Re: Rich running j2200?? Need help

Unread post by ZuluBen » Sun Jun 17, 2018 11:52 pm

What does your plugs look like?

Pull a few and post some pics?
Jakes
Pre-take off checks
Posts: 84
Joined: Mon Jun 04, 2007 3:21 pm
Closest Airfield: Louis Trichardt
Location: Louis Trichardt, Limpopo
Has liked: 0
Been liked: 0

Re: Rich running j2200?? Need help

Unread post by Jakes » Mon Jun 18, 2018 3:33 pm

Zuluben,

Here is one of each. Their "friends" looks exactly the same on each piston.

Jaco
You do not have the required permissions to view the files attached to this post.
Addicted to the smell of AVGAS!
User avatar
ZuluBen
Six Tousand
Six Tousand
Posts: 6593
Joined: Mon May 09, 2005 4:54 pm
Location: Gaborone, Botswana
Has liked: 6 times
Been liked: 3 times

Re: Rich running j2200?? Need help

Unread post by ZuluBen » Thu Jul 05, 2018 10:28 pm

Hmm that does look a bit rich...

Do 2 checks for us:
1) What is your fuel pressure with the engine running at about 2000rpm?

2) Some floats have been know to absorb fuel and become "saturated", so they do not produce enough float or lift to close the needle. Have a good look at the floats. Put them in a deep jar of Avgas and see how well they float. Take a pic,
User avatar
Flooi
Frequent AvComer
Posts: 872
Joined: Fri Apr 20, 2012 10:29 am
Closest Airfield: FAHG
Location: Nigel
Has liked: 49 times
Been liked: 19 times

Re: Rich running j2200?? Need help

Unread post by Flooi » Wed Nov 14, 2018 8:42 am

Any news on this?
Hennie van Zyl
IWG
Tripped over wheel chock
Posts: 28
Joined: Tue Aug 08, 2017 2:47 pm
Closest Airfield: FAGM
Has liked: 0
Been liked: 1 time

Re: Rich running j2200?? Need help

Unread post by IWG » Thu Nov 15, 2018 12:05 pm

Hi Jakes

One thing that will also seriously richen the mixture on the SP470 is a damaged pressure compensation pipe or a blockage of the port on the carb or the one on the air box.
You should be able to blow through the little stub into the air box and with the float bowl removed you should be able to blow through the one on the carb.

IWG

Return to “Jabiru”