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New member of the 'Sinker Club' (carb floats)

Latest float version?

Are these the 861-188 floats? Seem to be the -184 floats.

I bought a set of the 861-188's from Lockwood last week.

-nick
 
Lockwood, Leading Edge Airfoil, and California Power all have them on back order. (The -188 which is the latest. )

Will try Aircraft Spruce by phone tomorrow. Web site did not have 188s
 
I am doing my first inspection on my 12. All of the carb floats are over weight.
Have not been able to locate any replacements. All Rotax dealers tell me they are back ordered currently 30 days or indefinitely.

I only have 74 hours on the carbs.

Now that sucks.

Type and brand and octane of fuel you run? 100LL or MOGAS? What brand of fuel?
 
I'm frankly tired of replacing my floats - my 4th set just went bad (almost 600 hrs on the engine). I'm certainly not impressed with the quality of the Bing floats, or rather, I'm highly negatively impressed.

I'm actually experimenting with the MS floats. I measured the pin depth of known good Bing floats and the MS floats and found that the MS pin depth was approx. 1/32" lower than the Bing floats which means a slightly higher fuel level in the bowl - I wasn't sure how that would affect engine running. I've just recently started test flying the MS floats. I've been approaching it carefully and only have about 10 hrs on the MS floats. Various power settings from low RPM to WOT, altitudes, attitudes, multiple take-offs, etc. So far I don't see any difference between the MS floats and the Bings. Power, temperatures, etc. all seem perfectly normal so far.
 
I'm frankly tired of replacing my floats - my 4th set just went bad (almost 600 hrs on the engine). I'm certainly not impressed with the quality of the Bing floats, or rather, I'm highly negatively impressed.

I'm actually experimenting with the MS floats. I measured the pin depth of known good Bing floats and the MS floats and found that the MS pin depth was approx. 1/32" lower than the Bing floats which means a slightly higher fuel level in the bowl - I wasn't sure how that would affect engine running. I've just recently started test flying the MS floats. I've been approaching it carefully and only have about 10 hrs on the MS floats. Various power settings from low RPM to WOT, altitudes, attitudes, multiple take-offs, etc. So far I don't see any difference between the MS floats and the Bings. Power, temperatures, etc. all seem perfectly normal so far.

Great update Tom, thanks!! I have no confidence that Bing will ever fix our problem, so a permanent fix would be great. Please keep us updated on your testing. Paul
 
I'm frankly tired of replacing my floats - my 4th set just went bad (almost 600 hrs on the engine). I'm certainly not impressed with the quality of the Bing floats, or rather, I'm highly negatively impressed.

I'm actually experimenting with the MS floats. I measured the pin depth of known good Bing floats and the MS floats and found that the MS pin depth was approx. 1/32" lower than the Bing floats which means a slightly higher fuel level in the bowl - I wasn't sure how that would affect engine running. I've just recently started test flying the MS floats. I've been approaching it carefully and only have about 10 hrs on the MS floats. Various power settings from low RPM to WOT, altitudes, attitudes, multiple take-offs, etc. So far I don't see any difference between the MS floats and the Bings. Power, temperatures, etc. all seem perfectly normal so far.

What brand and type of fuel are you running in your RV-12 with 4 bad sets of floats?
 
I just looked at MS website... Is $125 for single float or pair of floats (I hope, I hope)?

$125 for two floats, $250 for both carbs. Plus something like a $7 processing fee and $30 shipping.
 
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Rediculous

These things can't be gold or platinum coated can they? This problem can't be unique to 912s installed in Vans RV-12 can it? Why can't this problem be solved by the manufacturer of the Rotax engine?

Apparently, Rotax doesn't give a d**n or maybe they like the steady income from the sale of floats. They say that there are many thousands of Rotax engines flying- right? Do the Europeans have this same problem? WHY is this happening? It really makes me sorry that I am building an airplane which requires the Rotax to be ELSA legal and cements my desire to build an RV-9 with a good dynasaures Lycoming. I'm pretty unhappy in anticipation of replacing Rotax floats every 50 - 150 hours or one year - whichever comes first.

I'm especially interested to know what problems the Europeans are having with Rotax 912 floats. :(:(:(:(:(:(:(:(:(
 
E. D. --

We are past the 400 hour mark on our RV-12, still using the original floats. Premium ethanol free MOGAS almost all the time, with an occasional tank of 100LL. I can't answer why we have had this experience and some others are having to replace theirs often... but this is certainly not a universal problem.

There's nothing keeping you from making changes to your E-LSA after certification, and for that matter nothing keeping you from making changes beforehand and going E-AB. And if you think Rotax maintenance is bad, I don't think a Lycoming would be all that much better. Magnetos don't last forever, for one thing. There's no perfect solution.
 
Odds are you'll be fine. My 12 has 400TT and a friend's 12 has 130TT. Both machines running original floats with 93E10...
 
My floats were replaced at 500 hour overhaul of the carbs, but the originals still pass the weight test, so I keep them as spares.
 
Just Lycoming was mentioned...

Just because Lyc was mentioned...

You could do a UL Power engine...no carbs, no mags...just sayin’. ;)
 
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and another one joins the club

Burgundy Baron is down for "5-6 weeks" per LEAF for replacement float. :(

If anyone finds a vendor with a shorter lead time, please let me know.

thanks,
-dbh
 
Dave

Are you waiting for Bing floats?

I think if/when I have to replace my floats I will switch to Marvel-Schebler MS80-430 Blue Epoxy Float. I say this with a little trepidation because I have tried numerous times to contact MS regarding their claim of "withstand extreme temperature changes and are truly unsinkable when exposed to the elements!"

MS never responded to my inquires. If the floats have the correct buoyancy and "float" at correct height then they should be good-to-go. MS makes lots of carb floats from this same material and I would assume they have done materials testing in 93E10 as well as avgas.

MS never answered my questions up until last week when I asked if their list price was for a single float or a set of two. $125 is for two floats to retrofit one carb. So, I guess price isn't too bad if floats work as advertised and last for a lifetime.
 
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Do take the time to check these floats. I just checked 4 on an RV-12 that had all of them replaced late last year with the latest and greatest floats.

I weighed them yesterday and they were 10.6 and 8.5 grams respectively.

The customer did say the one side would intermittently overflow the carb.

Vic
 
Do take the time to check these floats. I just checked 4 on an RV-12 that had all of them replaced late last year with the latest and greatest floats.

I weighed them yesterday and they were 10.6 and 8.5 grams respectively.

The customer did say the one side would intermittently overflow the carb.

Vic

Vic, how far reaching are reports of float problems?
 
Bad Floats, Bad Fuel

Thanks for previous replies, - it seems that as well as sunk floats I had faulty, aged fuel. My situation & lifestyle sees me flying (or attempting to) only every few weeks or more. I had only 1/4 of a tank sitting for several weeks & after it was drained & refilled with Avgas 100LL the engine ran smoothly on the ground,- (unable to take it up due to inclement weather.) People here tell me that most schools with aircraft powered by Rotax 912 ULS engines use fresh BP95 Octane Mogas. Emphasis was placed on the fuel being FRESH. On my most recent attempt to get in the air I have discovered my fuel tank leaking from the level sensor plate on the front of the tank. When that new little problem is fixed I will try once again to commit Aviation. Cheers, DEAN
P.S, Mankind has sent men to the Moon, - how come we can't produce floats that float & continue to float??
 
Thanks for previous replies, - it seems that as well as sunk floats I had faulty, aged fuel. My situation & lifestyle sees me flying (or attempting to) only every few weeks or more. I had only 1/4 of a tank sitting for several weeks & after it was drained & refilled with Avgas 100LL the engine ran smoothly on the ground,- (unable to take it up due to inclement weather.) People here tell me that most schools with aircraft powered by Rotax 912 ULS engines use fresh BP95 Octane Mogas. Emphasis was placed on the fuel being FRESH. On my most recent attempt to get in the air I have discovered my fuel tank leaking from the level sensor plate on the front of the tank. When that new little problem is fixed I will try once again to commit Aviation. Cheers, DEAN
P.S, Mankind has sent men to the Moon, - how come we can't produce floats that float & continue to float??
Bing carbs are from Germany... I am part German myself. That country, despite great car design and huge profit margins, still hasn't sent a man to the moon.

Failure usually has to do with a sub contractor. Think Morton Thiokol, failed seals with liquid hydrogen, and the Challenger failure.

Bing Carbs got a new vendor for the floats, probably to cut costs. They are foam and don't seem to do so well as the previous vendors products. If we could find the name of the company that makes the floats for Bing Carbs, perhaps it could be addressed, the problem.

There are aftermarket parts from MS that are available, for half the price.
 
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Seems like another type of floats have been issued; Part No.861189. Hopefully this will end this sad saga.. Cheers, DEAN
 
Auto fuel formulas?

I will complicate this plot with an experience I have. My Stewart systems water based paint job blistered whereever auto fuel was spilled or leak on it. Stewart advised me at OSH that autofuel has injector cleaners in it that AV fuel does not.
So, if 100LL never causes a float problem and SOME auto fuels do, it may be a branding/formulation specific problem ? FWIW, my mogas is 91 no alc and that blisters the paint.
 
I'm frankly tired of replacing my floats - my 4th set just went bad (almost 600 hrs on the engine). I'm certainly not impressed with the quality of the Bing floats, or rather, I'm highly negatively impressed.

I'm actually experimenting with the MS floats. I measured the pin depth of known good Bing floats and the MS floats and found that the MS pin depth was approx. 1/32" lower than the Bing floats which means a slightly higher fuel level in the bowl - I wasn't sure how that would affect engine running. I've just recently started test flying the MS floats. I've been approaching it carefully and only have about 10 hrs on the MS floats. Various power settings from low RPM to WOT, altitudes, attitudes, multiple take-offs, etc. So far I don't see any difference between the MS floats and the Bings. Power, temperatures, etc. all seem perfectly normal so far.

Tom

I’m re-reading the entire “float” thread again and I have a question on your post…

You say that the MS (blue) float has the pin located at a different height compared to the black Bing float – maybe by as much as 1/32”. The Bing floats are symmetrical with the pin in the middle, so no top/bottom orientation during install. If the MS float has the pin offset then it will matter which way it is installed. And perhaps, by having the pin offset, this becomes the key to having the correct fuel level in the bowl.

To sum up my thoughts… we’re thinking the blue MS floats may weigh slightly more than 7 grams/pair which means they are less buoyant and float at a lower level. If the actuator pin is raised to compensate then maybe all is good. The key here would be that the MS floats may be slightly heavier but shouldn’t gain any weight because of magic material they are made from. So once installed, they should behave for a very long time and stay on a diet and not get chubby.

If it’s not asking too much, maybe those of us using blue MS floats can chime in with their experience.
 
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I posted this in October:

?I purchased and installed a pair of the Marvel Schebler floats. Weight out of the box was: 3.7 and 3.8 grams. They replaced a pair of Rotax floats that weighed 8.4 and 4.7 grams on removal. Needless to say I had a severe leak out of the overflow tube on my right carburetor.
Works great now.?


I noticed a strong fuel odor in flight which is why I started looking for a problem. The Bing/Rotax floats were over weight and one of the brass pins was very loose. I have not checked the floats in the left carburetor yet, but I have a pair of the MS floats ready to install.

Maybe the new Bing/Rotax floats will be better, but for me, the MS epoxy floats were a better alternative. MS has been using this material for carburetor floats for a long time.
 
I posted this in October:

?I purchased and installed a pair of the Marvel Schebler floats. Weight out of the box was: 3.7 and 3.8 grams. They replaced a pair of Rotax floats that weighed 8.4 and 4.7 grams on removal. Needless to say I had a severe leak out of the overflow tube on my right carburetor.
Works great now.?


I noticed a strong fuel odor in flight which is why I started looking for a problem. The Bing/Rotax floats were over weight and one of the brass pins was very loose. I have not checked the floats in the left carburetor yet, but I have a pair of the MS floats ready to install.

Maybe the new Bing/Rotax floats will be better, but for me, the MS epoxy floats were a better alternative. MS has been using this material for carburetor floats for a long time.


Do you run Mogas with E-10, or ?
 
The new Rotax SI that refers to new part numbers and is just that for some parts. The floats got a new part number, but are the same floats. There is no swapping out. Some of the other parts just had the gold anodizing removed and got a new part number because Europe ban the gold anodizing because they said it could cause cancer.

The Schebler floats are too heavy. This displaces more fuel inside the float bowl and that means the float armature needs to be adjusted to account for the extra fuel displacement. I haven't seen anyone here comment on how much fuel is displaced or how much they adjusted their float armature.
 
... The Schebler floats are too heavy. This displaces more fuel inside the float bowl and that means the float armature needs to be adjusted to account for the extra fuel displacement. I haven't seen anyone here comment on how much fuel is displaced or how much they adjusted their float armature.

See post #57 in this thread. I'm up to about 15 hrs with the MS floats without any ill effects that I can see. I've tried various altitudes & throttle settings. I have noticed about a 30 deg EGT difference at lower RPM (5000 - 5200) and I frankly don't know if that existed before.

This is without any adjustments to the carbs. I have a 600 hr inspection coming up and I'll probably make a slight adjustment to account for the slight change in the float pin depth.
 
I'm thinking the experiment that needs to be done would be to ?float? a Bing and MS in an open dish of gasoline (93E10 or 100LL). Use a piece of piano wire as a guide through the float bushing so the float stays vertical. Measure each float?s actuator pin with respect to the surface of the gasoline.

Let?s say the MS is less buoyant (slightly heavy) and maybe the pin is 1/32? lower in the above experiment as was reported by tomkk in an above post. In this example the float level would be +1/32? (0.031?) higher than the Bing.

So, a few things?

  • Some guys are already using MS with reports of success.
  • If we can determine the difference in buoyancy from the above experiment, perhaps we can readjust the needle valve shutoff position on the carb to compensate and keep float level per Bing spec.
  • Or, maybe a slight difference in float level doesn?t matter too much in a carburetor that is used in an airplane. Imagine what the floats are seeing when the airplane is in bumpy air ? the entire quantity of fuel in the bowl would sometimes be thrown to the side or vertically to the top of the bowl. I would guess that the carburetor fuel bowl is a rather violent place when the airplane is in flight. It would be interesting to know how well the floats control fuel level in various flight regimes.
 
I?ve been through two sets of floats this year already. I?m told the new ones are clearing customs this week.
 
...
  • ...
  • ...
  • Or, maybe a slight difference in float level doesn?t matter too much in a carburetor that is used in an airplane. Imagine what the floats are seeing when the airplane is in bumpy air ? the entire quantity of fuel in the bowl would sometimes be thrown to the side or vertically to the top of the bowl. I would guess that the carburetor fuel bowl is a rather violent place when the airplane is in flight. It would be interesting to know how well the floats control fuel level in various flight regimes.

That was actually what I was thinking that prompted me to experiment with the MS floats. Fuel has got to be sloshing around inside the bowl just from normal engine vibration, although there could be come counteracting forces that might dampen that. Beyond me - all I know is they seem to be working OK so far.
 
Burgundy Baron is down for "5-6 weeks" per LEAF for replacement float. :(

If anyone finds a vendor with a shorter lead time, please let me know.

thanks,
-dbh

Good news! Despite the original quote of 5-6 weeks, LEAF delivered a pair of floats (861 189's) yesterday. :) Hopefully they received enough to clear out everyone's back orders, so we'll all be able to find out if the 189s work any better.
 
You guessed it? new member here. Yesterday I flew with my friend in his 1-year old RV-12 S-LSA with 130TT. I smelled a whiff of gasoline on take-off and on initial climb. We flew 30 miles and landed/relaunched again with same smell of gasoline. Flew another 30 miles and landed and this time shut off the engine. On engine restart we had extreme roughness and zero power. Upon exiting the aircraft there was a puddle of fuel on the ground. We removed the top cowling and ran the electric fuel pump to discover fuel pouring out of the right carb air filter.

The airplane had to spend the night and we got a long car ride home from a friend. This morning we gather tools and a spare set of Bing floats and set out to bring the plane home. We removed the floats from the offending carb and weighed them on the spot at 8.83 grams. The spare floats I had are actually
?heavy? floats sent to me by Paul Straub. I was going to experiment and try to lighten the floats but never got around to it. Anyway, I measured the floats this morning and they were 6.3 grams. They must have dried out over time. We used these floats to fly home and will replace soonest. I suspect floats that once absorb fuel will do so again ? probably in short order.

So, a few observations?

1. Floats weighing 8.83 grams will sink to the point of allowing raw gasoline to flow out the inlet of the carb and drip from the air filter.
2. If you smell fuel on take-off or initial climb you probably have heavy floats and a fuel leakage is occurring.
3. On closer examination we see the discharge end of the clear overflow tube that tucks into the float bowl bail wire has a deformed end. Instead of a clean flush cut, the end almost looks melted. Perhaps fuel was leaking over-time and distorted the end of the tube?
4. We will add a set of dried-out floats to the list of spare parts carried in the airplane.

Now for the hundred?s-of-dollar?s question?

Do we buy Bing or Marvel-Schebler floats? I?m leaning toward Marvel-Schebler. Perhaps a show of hands from the guys using MS floats and what their experience has been so far. The detractor I have with MS is they don?t answer emails and that just leaves a real sour taste in my mouth.

Any and all advice appreciated?
 
If you can find MS80-430 or MS80-431 on their website, go order some. Not sure, but they seem to have currently been removed from the marketplace. or at least from their website, online. Might have to give them a call. Or maybe someone's email about their guarantee decided to make the legal department there remove them altogether.

I was looking at this website for Bing Carb rebuild kits, and floats. Interestingly, the kits are marketed as Alcohol Resistant . Not Alcohol proof. Things that make you wonder how serious Bing is about solving this problem, or Rotax, for that matter, since motorcycles don't run AVgas at all, and are at the whims of Mogas fuel makers for Ethanol and other additive content.

http://bingcarburetor.com/store/p73/ALCOHOL_RESISTANT_FLOAT_&_BOWL_KIT.html

Maybe one day we get a bolt on aftermarket fuel injection kit for the 912 ULS, and put an end to this nonsense on Bing QC, leaky carbs, bad floats, and fire hazards.
 
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Floats

I talked with the MS guy at Sun 'N Fun about the floats. He said they are out of stock right now so they took them off their web site. When they get them back in stock, they will be back on the web site.

He said these floats are made of the same material and in the same manner as the floats they make for certified engines. He also said in their testing, the fact that they weight more than the bing floats does not matter.

I don't have to buy any right now, but when I do, I will consider MS floats.

A very experienced Rotax mechanic told me if you have to replace the floats, save the ones that are under the weight limit because you may need them in the future. Like you suggested, carry them in the airplane.
 
I have almost 35 hrs on my MS floats so far, no problems so far. I'll be doing a 600 hr inspection, probably later this week. I'll be doing a carb overhaul as part of that and I intend to look at the feasibility of making a small adjustment in the float armature to see if I can compensate for the slightly different pin depth (see one of my earlier posts). So far so good ...
 
Thinking Outside the Box?

The Marvel Schebler floats apparently are heavier than the 7 gram Rotax spec and will most likely cause fuel level to be high in the float bowl.

I have an idea to fix this. Marvel Schebler says their epoxy floats can be cut and punctured and still function as designed with no fuel saturation into the base epoxy material.

Bing designed the float to be symmetrical so that it can be installed without regard to orientation.

My idea is to remove some of the base material on the MS float to attain <7 gram weight. Either machine off some of the top of the float to reduce height and/or machine chamfered edges on the top side of the float. Either method will reduce weight, and if as MS says, the epoxy will remain sealed to fuel impregnation. With this modification the float will no longer be symmetrical and will require correct orientation during assembly.

I have sent this suggestion to Marvel Schebler and we?ll see if they respond. In the mean time, I?d like to get hold of a pair of MS floats and experiment with material removal to get weight under control.

Below are pics of original MS floats and floats modified for height/weight.



 
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