Great info Charlie, your experience is very similar to mine. I just received my new floats today, they are the same PN as yours, 861188. I weighed them and confirmed that they are physically the latest Rotax floats per their 2017 Service Bulletin (no dots and an internal brass sleeve). Like you, it was $300 for the 2 pair and I am hoping for the best...maybe these are better than my originals.

I'm beyond disgusted with this float quality issue. I had Lockwood perform the 200h inspection/maintenance on my carbs in March. They replaced all four floats at $150.95 a pair.

At 44 Hobbs hours, 7 months one failed while I was fortunately on the ground doing some other maintenance. It was at least 6 grams and was on the bottom of the bowl. The side pin in the failed float is actually loose and can be twisted around in the float. Clearly Q/A failure. The floats they installed in March were from two different batches and the one that passed looks like it has a rougher surface than the failed float. I'm trying to contact Lockwood to determine to whom this needs to be reported. Just unacceptable.

I quickly shopped around for a replacement and found some interesting things. First, cannot even find them on the Lockwood website. CPS, the other authorized Rotax dealer in California has them listed at $131.75 a pair. However, the winner is Aircraft Spruce where they are listed at just $93.50 a pair. You can even buy singles from them. Back ordered in the East, so I ordered them from the Western warehouse and just got them. However, I see this morning they are on "indefinite backorder" in both locations.

????

Hi Brent, good info. Yes...it should not be this difficult!! So the pair at Aircraft Spruce for $93.50 is PN 861-184, an older style. According to Rotax, the latest version is 861-188 per my prior post. So CPS shows the correct PN, with a price of $131.75/pair (they now show out of stock, because I just purchased their last 2 pair from what I can tell). Anyway, Spruce and CPS should have identical pricing because AS owns CPS, they are in the same building in Corona, CA. I am hoping this latest version will last at least a year!! Happy Thanksgiving!

Per post #17 above... Paul Straub is sending me two heavy floats which I should receive tomorrow. I have good selection of carbide burrs for my Dremel and a digital scale with 0.01 gram resolution. I plan on milling a cavity into the float and remove enough material to bring float back into <3.5 gram spec. I have some fresh Proseal which I can mix in correct proportions. I've been thinking about material to form the lid for the milled cavity. So far possibilities are thin brass, aluminum, or carbon fiber. I hope to mill the cavity from the top side of the floats so sealed surface is above the "water line" so-to-speak.

Jim,
I think the cavities will eventually fill with fuel through the porous material of the float, and you will be worse off than before. Just my opinion.
Alex

more info tidbits
 

In my original post (#19) there is a typo. I replaced the original 861 182 floats per SB in 10/2015 not 10/2016. The engine had never been fueled at that point. When I experienced fuel dripping onto the floor after the first flight in 9/2016 the floats had been immersed in fuel for only a few months and the engine had been run only about 3 hours. That suggests strongly that the problem is that the floats had some material flaw and could not tolerate being immersed in fuel. Engine vibration or heat radiated up from the exhaust pipe seem like logical possible culprits but exposure had been minimal at this time of failure.

My newest 861 188 floats all weighed 3.13-3.16 g dry. Another forum thread says new Marvel-Schebler floats weighed 3.7 and 3.8 g and as I explained before I don't think my carb would function properly with floats that heavy, unless the pin location is different. I got the 861 188 floats from Leading Edge Air Foils. I usually deal with Lockwood but they did not have any in stock. Phil Lockwood told me a couple weeks later that he did not have information on the Marvel-Schebler float development. This surprised me since Phil has been one of the Rotax gurus for a long time.

Also mentioned in that other thread is height of the fluid surface in the float bowl. But it looks to me like the fuel inlet for both the main jet and the idle jet is a brass orifice situated low in the float bowl, in which case height of the surface in the float bowl would make little difference. My problem seems to be floats so saturated that they don't close the needle valve and the float bowl overflows into the carb throat. Oddly, neither the carb synchronization nor the idle speed seemed to change during all the leaking.

Charlie -

Welcome to the club...

I haven't had a chance to carve up Paul Straub's heavy floats.

Paul S. - Do your new floats (with shortened brass slider tube) float at correct height in the carb bowl? Noticeable difference from the heavy floats?

Hi Jim, good question, I didn't think to fill the bowls with fuel and do a visual check. I installed 4 new floats (2 pair of PN 861188) It was raining all day yesterday, so the only testing so far has been a 5 minute engine run. No rough running at idle and no signs of any fuel leaks or overflow. They all weighed in at 3.1g - 3.2g before installation, so I would assume things should be fine for the next year or so.

pin position
 

My new, dry 861 188 floats (shorter brass tube slider) all floated with lower side of the pin just touching the fuel surface. Again, 3.13-3.16 g each when dry. This seems to be about as good as it gets. The engine once again starts instantly and smoothly, and runs smoothly at all RPM. 168 hours on it.

Any news on the Bing float situation?