%^##@!! Bing!!!!

[Aerofoam]

So.... did you actually weigh the floats or not?

Didn't weight them, I had 3 people tell me that if they are floating with the fuel at the level of the pin, or even slightly lower, they are OK.
They float with the pin even with the fuel level.
I do have another set of floats, so I can try that too.

 

[Tyger]

I wouldn't go by what "three people" just told you. One of my pet peeves in the Army was when some issue would come up and soldiers would say "Well, I was told...". I would say to them, "Who told you?" and "Show me where it is in the regs."
I got those max weight specs straight from the Rotax maintenance manual. If you're looking at the floats you might just as well weight them! You may just be surprised by the result.

 

[Sv.grainne]

I wouldn't go by what "three people" just told you. One of my pet peeves in the Army was when some issue would come up and soldiers would say "Well, I was told...". I would say to them, "Who told you?" and "Show me where it is in the regs."
I got those max weight specs straight from the Rotax maintenance manual. If you're looking at the floats you might just as well weight them! You may just be surprised by the result.

Especially given the specified weight tolerance!

 

[nishanh]

Took this lovely picture from my in-progress Calidus build. We were testing the fuel pumps and it started dumping fuel on the ground out of one of the breather lines. Removed the right-side float bowl and saw this. Additionally, the floats were adhered to the bottom of the bowl, preventing their operation. This is a brand new Rotax 914UL engine. The left-side photo is shown in comparison.



I'm doing the EFI upgrade after the warranty expires.

 

[Aerofoam]

I wouldn't go by what "three people" just told you. One of my pet peeves in the Army was when some issue would come up and soldiers would say "Well, I was told...". I would say to them, "Who told you?" and "Show me where it is in the regs."
I got those max weight specs straight from the Rotax maintenance manual. If you're looking at the floats you might just as well weight them! You may just be surprised by the result.

I compared the soaked floats to a set I pulled from another carb and the old floats were floating with the pin just submerged, the top surface of the pin was at the fuel level.
The dry float I compared floated with most of the pin above the fuel level, so there is clearly a difference. (about 0.035")
I took them in to town to weigh on a friends triple beam and no one was at the shop, so maybe today.

Me and a friend at another shop are thinking seriously about modeling the float and printing new ones....

 

[MikeBoyette]

I wouldn't go by what "three people" just told you. One of my pet peeves in the Army was when some issue would come up and soldiers would say "Well, I was told...". I would say to them, "Who told you?" and "Show me where it is in the regs."
I got those max weight specs straight from the Rotax maintenance manual. If you're looking at the floats you might just as well weight them! You may just be surprised by the result.

Yep the right way, the wrong way, and The Army Way!!

 

[Aerofoam]

Do you really think I just polled 3 random people off the street?
Really?????

Anyway, back to reality, the digital scale was worthless, multiple readings, but the triple beam showed 2 floats at 3gr and 2 at 4gr.
Not too excessive, especially considering I tried adjusting the tab over .035" upwards to apply more force and no result.
But maybe enough, at this point I hope it is the problem...
One of the rubber cone seals has a slight girdle from where it seats, but it is only about .003" and I have never seen this type of valve not seal do to this type of small depression from the seat.
This also wouldn't explain how it developed 3 days after new fuel, lines and starting attempt.
I checked the seats and cleaned them to no avail.
I will try swapping the dry floats next...

 

[Vance]

Anyway, back to reality, the digital scale was worthless, multiple readings, but the triple beam showed 2 floats at 3gr and 2 at 4gr.
Not too excessive, especially considering I tried adjusting the tab over .035" upwards to apply more force and no result.
But maybe enough, at this point I hope it is the problem...
One of the rubber cone seals has a slight girdle from where it seats, but it is only about .003" and I have never seen this type of valve not seal do to this type of small depression from the seat.
This also wouldn't explain how it developed 3 days after new fuel, lines and starting attempt.
I checked the seats and cleaned them to no avail.
I will try swapping the dry floats next...

My recollection is Bing carburetor floats on a Rotax 914 are supposed to weigh no more than three and a half grams each.

Four grams would be out of tolerance and should be replaced.

I have no experience with the two strokes.

My advice to you would be to find a manual that you trust, get a rebuilding kit and follow the procedures for rebuilding the carburetors.

In my opinion as old as they are they should be properly rebuilt.

 

[Tyger]

Do you really think I just polled 3 random people off the street?
Really????

Anyway, back to reality, the digital scale was worthless, multiple readings, but the triple beam showed 2 floats at 3gr and 2 at 4gr. Not too excessive...

You crack me up. When did I ever say "three random people"?
It would be best if you used a digital scale that was not "worthless", as you do need to weigh each float down to tenths of a gram, as per Rotax's instructions. And there's no such thing as slightly excessive, IMO.
I agree with Vance that it's probably a good idea to rebuild the carbs, but as new floats will certainly be part of that, you might just get yourself those first and see how they go.

 

[Sv.grainne]

I bought a small jewlers scale from Amazon last year before I did my 100hr maintenance. Weighed the floats and all ok. Also used it while I was balancing my prop, making custom weights out of longer blots and washers.

 

[Tyger]

I bought a small jewlers scale from Amazon last year before I did my 100hr maintenance. Weighed the floats and all ok. Also used it while I was balancing my prop, making custom weights out of longer blots and washers.

In my neck of the woods (NYC) it's very easy to find pocket-sized digital scales that weigh things down to tenths of grams...

 

[Aerofoam]

I just bought one that goes down to .005g. and does Ct. and gr. weights too....
I am having a friend model the floats in Solid Works, so we can try printing them and I can also print a negative to
use as a mold to make some out of carbon fiber, or fiberglass......

 

[Mcmanus]

Maybe it will help you, I looked carefully at these files before attaching them here, there are complete notions.
Buona giornata.
Fabio - Monza GMT 8.52 am

 

[Aerofoam]

Thank you, the exploded diagram in type 54e is excellent!

Maybe it will help you, I looked carefully at these files before attaching them here, there are complete notions.
Buona giornata.
Fabio - Monza GMT 8.52 am

 

[Mcmanus]

Okay! Grazie a Te! spero tu possa risolvere il problema. ;-)

Monza - GMT 11.48 am

 

[GyroChuck]

Found this on the EAA website. Not your problem but a little more helpful info on the Bing carbs.

*

Throttle Cable Boot For Bing Carb

 

[rcflier]

Not being an EAA member - could you give me the short version, please?

 

[Rattler 1]

Not being an EAA member - could you give me the short version, please?

The throttle cable boot on top of the carb can leak air into the carb if it's cracked thus causing it to run lean and possibly overheat EGT's.

 

[Rotax Rick]

The level should be 1/4 inch below the top of the float bowl with the floats floating in the gas. Regardless the angle of the arms you bend the tab until you get the 1/4 inch level. If fuel is running out the overflow hoses the tab needs to be bent more. Then if you cannot achieve this without having to go to a crazy angle then I recommend checking the floats . Rotax Rick

 

[Rattler 1]

The level should be 1/4 inch below the top of the float bowl with the floats floating in the gas. Regardless the angle of the arms you bend the tab until you get the 1/4 inch level. If fuel is running out the overflow hoses the tab needs to be bent more. Then if you cannot achieve this without having to go to a crazy angle then I recommend checking the floats . Rotax Rick

I agree, this is not that difficult.