Bing 54 flooding at idle on decent

[danawalker2@gmail.com]

I have a cauna 3 cylinder motor with 3 bing 54 carbs. The engine runs great. It idles a little ruff. When on approach to land when pulling the throttle back to idle it will studder and stall, only while decending to land and no other time. If I keep the rpms up over idle it will not happen but I have to have a longer approach as I am still with some thrust and slowing down becomes harder.
I have tried to give extra fuel for choke to test if it was too much fuel or not enough as the problem but no change. I have also tried to catch it by giving throttle but can not always catch it before stall.
What could be the problem. It could be 1 or 2 of the carbs doing it and not all three.

[Mike Switzer]

I haven't messed with a Bing carb in over 20 years, so this may not apply, but a lot of the time flooding at idle is caused by the float valve being stuck open.

[danawalker2@gmail.com]

That is a good point but it will idle on the ground fine. It only happens in Neg G on decent. It must still be due to gas rising into the venturi but how if the floats are shut. Once on the ground it restarts fine and idles fine.

[Bill Greenwood]

I don't know that engine or carb, but what you describe sounds like carb ice if it was in an 172 or similar.

[martymayes]

It only happens in Neg G on decent.

Yes, neg G will stop the fuel flow in a float carburetor....

I'm guessing you mean nose down in a descent. Most likely one carb bowl is overfilling, float level too high or a leaky needle valve/seat. Need to isolate which cylinder is being enrichened.

[danawalker2@gmail.com]

That makes perfect sense. I have set all 3 exactly the same and I used to have a problem due to vibration of a carb every once in a while over filling and loosing fuel from the over flow vent. I thought it might be a sticky float shutoff needle not fully seating. But, because it was random I could not pin point the cause.

Thank you all for your help.

[Mike Switzer]

Could be the nose down attitude is putting one of the floats in a position in which it will bind up. A lot of times float problems are intermittent & a real pain to troubleshoot.

[Flymax]

I have 2stroke 2cyl. opposite WALTER M202 engine with 2 BING 54 carbs and the same problem. At iddle it has 1700 rpm., but at descent 2500-2800., and fall they down just after touchdown. I have done everything, but I can,t belive, that this problem we have just we two! Have You solved it? I know fuel quality screws on my carbs are almost closed for best run, and I think, there is no air intake for iddle rpm. and carbs work at next "low rpm. level". Iddler jets orriginally are 50 , so I think to change them to 55 , open quality screws, and descend carb. pistons with quant. screws. Have anybody tried it? Thank You for Your help!