Bing carbie

[facthunter]

Check your fuel pressure if you haven't done already (it might be too high) and ensure the dashpot slides freely and is installed with the little lug on the edge of the diaphragm in the right place. That's the only thing that locates the slide (which is a pretty crap set up). Normally an error in the float level affects idle and low down power most.  Nev

 

 

[dan tonner]

Hello Yenn;

 

     This is just a shot in the dark, but:

 

     Is it possible the o-ring which should rest  on top  of the needle circlip in the diaphragm piston (and just below the fixation screw) has somehow found its way  under the circlip?  This would result in a higher needle position and an over-rich mixture;    or;

 

    as alluded to by SkippyDiesel above, there was a recall on ROTAX floats for the Bing Carbs a couple of years back. The Rotax 912 floats are actually two independent "foam-style" blocks in the float bowl made from synthetic material (as opposed to the connected pair of hollow "bobbers" used on most altitude-compensated motorcycle engines). There was an issue with a limited number of Rotax floats whereby they became "waterlogged"  (gas-logged???) and failed to close the inlet needle valve properly. 

 

     If your carbs are equipped with the "Styrofoam-style" floats, you might want to Google the following Rotax Service bulletin:   Rotax SB-912-065   -   Carb Float Buoyancy

 

Good hunting;

 

CanadaDan

 

 

[Yenn]

Problem solved. When I stripped the carbie initially I removed the cover and the slide, with the spring. I thought I had marked which way it was assembled and returned it the same way.

 

Today I phoned Jabiru and talked to Lee. From my description of the problem he said it was most likely that the piston and diaphragm were incorrectly replaced.

 

I of course said I had marked it, so we talked about other problems it could be.

 

I asked which way the two inlets to above the diaphragm should point. Lee didn't know without taking a look at a carbie, I just thought they should point upstream to work and I had them pointing downstream.

 

It only took a couple of minutes to take the top off, find the alignment tab on the diaphragm and sure enough it was not in the correct location, Turn it 180 degrees to correct location, the two inlets now point in the direction I expected. An hour later and it is installed on the engine and a test run shows it is all good.

 

What a stupid mistake, I can't work out why I marked it incorrectly. Old timers disease catching up maybe.

 

Thanks for all the advice and I have learnt that the quickest way to solve a problem is to go to the experts.

 

 

[skippydiesel]

Problem solved................................................................................

 

What a stupid mistake, I can't work out why I marked it incorrectly. Old timers disease catching up maybe.

 

Thanks for all the advice and I have learnt that the quickest way to solve a problem is to go to the experts.

 

Great new - well done.

 

As for the mistake - we have all done similar, dont be too hard on yourself. In fact you did well - following each line of possibility , consulting widley and eventually finding & remedying the problem.

 

 

[Downunder]

the diaphragm and slide in the correct location? You will notice a little alignment lug on the diaphragm that sits in a little rectangular socket

 

M61A1 was on to it.

 

And now I know what the symptoms are....and that the engine will still run....

 

Great thread.

 

 

[facthunter]

And my post #26. I dare to mention..  Nev

 

 

[Yenn]

M61A1 and Nev. You were ahead of me. I mis marked it and didn't pick up on your references to the locating tab.

 

Thanks anyway I should have been more observant.

 

 

[M61A1]

M61A1 and Nev. You were ahead of me. I mis marked it and didn't pick up on your references to the locating tab.

 

Thanks anyway I should have been more observant.

 

I only know because I’ve done it myself.  Make enough mistakes and you get to be an expert. ?

 

 

[facthunter]

 I actually reckon it's a barely good enough for the job, carby . Flooding float type carbys are not for aeroplanes and there are other CV types far better quality. been made but not so available. Over the years there's been more than enough issues.. . and they are located in a poor position  as well on the Rotax. and the silly pull the knob out of the dashboard to close it feature.   Nev

 

 

[Thruster88]

 I actually reckon it's a barely good enough for the job, carby . Flooding float type carbys are not for aeroplanes and there are other CV types far better quality. been made but not so available.   Nev

 

Um ? all Lyc and Continental carb engines have float chambers? Have heard with pommy constant depression carbureters it's the owner that suffers depression.??     

 

 

[M61A1]

Maybe it’s a shame the Germans lost WWII. They had fuel injection in the 30s. 

 

 

[Yenn]

I had thought of replacing the bing with the aeroinjector, as used in the sonex. Cost US$499, plus I would need a pressure reducer and new throttle control. Probably also need to fit EGT gauges,so not a cheap alternative.

 

Regarding fuel injection, the poms had it in the fifties. The Conquerer tank was fuel injected with a mechanical set up. I was a mechanic and one came in running rough. Having no experience I went to the office to find a maintenance manual, only to be told it was secret and I didn't have clearance to see it. I had to fix it and I did, but I cannot for the life of me remember how I did it. The poms also had a lot of other things and I doubt that any of them were as good as the German or US stuff.

 

 

[facthunter]

The BING does have flooding issues, you can't deny that and most other carbs on planes are better made. I don't like any float carbs on planes They are a serious fire risk where there's red hot exhaust pipes all around, and below the Carbs. Yeah" Mines never caught on fire". Doesn't prove much.  Nev