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

[Larry DeCamp]

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.

[NinerBikes]

New part number with a red "R" on the floats, now ending in -189.

[Piper J3]

Originally Posted by tomkk

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.

[mdoyle]

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.

[NinerBikes]

Originally Posted by mdoyle

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 ?

[mdoyle]

95% Mogas with E10

[NinerBikes]

Originally Posted by mdoyle

95% Mogas with E10

If I ever get back to Hamvention in Columbus/Xenia, in May, I'd like to see your bird.

[Jolly]

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.

[tomkk]

Originally Posted by Jolly

... 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.

[Piper J3]

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.