Rotax carb floats sinking

[HansLab]

Hi y'all,
After having sold my fine Kitfox IV I'm building a RV12 now: quite different engineering for starters, and who knows how it will fly.
These types of RV suffer from sinking 912 Bing floats. I refuse to believe that this is an RV12-only issue - but I can't find any info on this Kitfox forum, either.

Floats tend to sink, therefore fuel keeps running, with al risks from that moment on.
Anyone knows this specific problem, too?
Or has a suggestion to solve it?

[Av8r3400]

It is not an RV-only issue. This is common on all 912 carburetors. Rotax has updated the floats many times.

There is now an aftermarket source (Marvel-Schebler) for floats that are supposedly of better quality, but more expensive. The jury is still out on weather they are any good.

[Slyfox]

the latest problem from an rv12 user was that he came out and said that he doesn't fly very often, in fact his aircraft was sitting for up to a year I think and he and half tank with auto fuel.

[Slyfox]

now with that said. I've not had any problems with mine. my engine is a 2009 year 912uls. I do fly a bunch and have fresh auto fuel in mine. I do check them at least once a year. never a problem

[avidflyer]

Your floats should not weigh over a certain amount. 3.5 grams if I remember right. But check that number out to make sure. You can use a jewelry scale to weigh those small weights. JImChuk

[Slyfox]

yes you can. but also keep in mind, when your lower the bowl and look inside you can tell if one float is sunk or both. have seen it, didn't have to weigh them.

[Dave S]

Similar experience as Steve/Slyfox

Our Kitfox has a 2008 912ULS and the floats have always checked out, no problems with sinking to date. It seems I recall some skuttlebut a few years ago that Rotax recommended replacing certain models of floats - and the replacements absorbed fuel more readily than the originals.

I am of the opinion that if they aren't broke - don't fix it; but, if they are broke - try a new set. I regard the floats as an "on condition item" period.

[Slyfox]

I'm constantly hearing that people are having problems with their carb rotax's. I've had a number of years and hours of enjoyment with my rotax. I think the most important thing to remember is: fly often, keep fresh gas in the tanks, do your maintenance. clean the filters, clean the jets, just keep up on the little wonder. I love my rotax and it always runs and fly's all so great. love my plane.

[Dusty]

I replaced my floats with the new better ones and got a couple of dud's.unfortunatly I threw the old "faulty" but within spec ones away.
out of desperation I raided an old 2 stroke for a good set.These have not let me down,my check is to clamp the fuel pipe,remove the bowl,sit it on a level surface and check visually the floats are level and the fuel level is at a previously scribed mark inside the bowl.Its a 5 Minute check and gets done as part of a 25 hr check,no problem anymore!

[Slyfox]

I believe the visual is always better. sometimes I feel that maybe the weigh scale might not be the right thing, just because 3 grams per float, now how accurate is the scale. I generally do mine at 50hrs during oil change

with that said, I am starting to believe that there might be a touch of conspiracy here on the part of Rotax. what am I talking about. think about it. all of a sudden, well over the last 10 years for sure, we have had a change in the fuel pump and the floats. The older equipment was really good. I think Rotax is wanting people to get sick and tired of the carb motor so that people will go for their fuel injected models. Just my thoughts, but there you go.