I think my floats flunked.

[cactusman]

So today was clean-up day. I had been getting that intermittent ACTV ADHRS VIB warning so I installed the new Vans rib in the back (what a pain - I highly recommend current builders do it while they can if it is not in the new kit), and I decided to check my floats to comply with the newly revised Rotax mandatory s/b....mainly because on my last flight I detected some fuel smell on decent, some erratic fuel PSI and FF readings, and a check showed some gas in left carb tray.

The carbs were balanced, and I don't notice any rough running - in fact during the last flight I was quite pleased with how smooth straight and level the airplane was running.

The syringe kits are not out yet so I calibrated and used my reloading scale, I could tell right away I was going to flunk as one float on the left carb (same side as the smells and overflow) was submerged and was noticeably heavy when I took it out of the fuel in the tray - even several hours after "drying out" (S/b calls for 2 minutes btw). Also the left cork float chamber gasket was apparently not installed correctly as there was a pinch in it when I removed it:



(the pair is supposed to weight 7 grams or less)

Here's the offending one (the "sinker"):



this one looks like it is going too....if a pair is supposed weigh 7 or less, I guess 1 should weigh 3.5 or less?



the "other side":

[JerryH]

Wow John you just got your plane in the air! How long have you had fuel in the carbs before this tear down?

[cactusman]

Originally Posted by JerryH

Wow John you just got your plane in the air! How long have you had fuel in the carbs before this tear down?

The plane has approx 8.5 hobbs, 5.3 flight...I just finished Test Card #3. The engine is in the affected range (although I think these floats sinking have been ongoing problems for more than a few)

Technically I had already installed and ran the engine a few times when the mand s/b came out - so I and some others I spoke with more in the know felt I had 25 hrs/60 days to comply....but the fuel smell and leaking carb dictated that immediate compliance was the better part of valor.

I guess that was the right call.

[f1rocket]

The question now is "What to do now?". There's no replacement parts designated and as you've noted, the test kits aren't even out there yet. I suspect I have a bad float as well as I get a whiff of gas occasionally, but I don't see a point in tearing everything apart waiting months for parts to come. Do you replace the float with another similar float until the new ones are designed?

[Hotscam]

Checked my floats a week ago as The engine is in the affected range.
7.1 grams for the two, so ok
This works much easier than the syringe job

[Top Cat]

Originally Posted by f1rocket

The question now is "What to do now?". There's no replacement parts designated and as you've noted, the test kits aren't even out there yet. I suspect I have a bad float as well as I get a whiff of gas occasionally, but I don't see a point in tearing everything apart waiting months for parts to come. Do you replace the float with another similar float until the new ones are designed?

The way I read the SB you have to replace BOTH floats, even if they're the 'faulty' types (since the new ones have yet to be developed. Trouble is you can't find even used 'faulty' floats to replace until the new ones are available.

You also have to replace the gasket?but if that's pretty new why can't you check it and re-install? A fellow pilot installed a new one and it leaks!!

[Bill_H]

The thing that gets me - How hard is it to design a carb float and select a material that doesn't absorb gasoline? Any HDPE or inert Teflon variant should do. Ridiculous! But then again, they recently shipped fuel hoses that couldn't withstand fuel...

I mean - carbs have been around for more than 100 years!

[cactusman]

I called Lockwood, and they are sending me 4 new floats (they will sell them separately) and two of their gaskets. Total cost is $173.76 inc shipping. They are also sending me a warranty form as well to ship everything back to them.

So we will see what they cover.

Total time to remove everything and test the floats took me approx 1 quarter of the Cardinals game. (45-60 minutes) - I had to unsafety the two air filters, loosen the carb clamp, undo the spring and then carefully unlatch the carb bowls (they are full of fuel btw).

3 of the 4 floats were bad. 1 was a sinker, the other two weighed close to or more than 3.5 grams dry.

The "other" method says that max allowable weight of both floats together is 7 grams.

But when I weight my good one - it is less that 3 grams (the video also shows that)....so perhaps all these floats are susceptible to saturation and possible sinking at some point or the other?

Based on my searches of past threads my guess is a good percentage of RV-12 owners have gasket/float/needle issues in their Bing carbs at one point or the other.

Not sure why Van's doesn't follow Lockwood's lead and replace those crappy cork gaskets on the float bowls as a start, but that's not my call. The worst part was that I thought I had a fuel leak somewhere so you start draining and tearing out fuel tanks and checking the fuel connections - all were fine btw.

My advice if you smell fuel while flying in the RV-12, start with the carbs - probably a bad gasket at the least, maybe a bad float or plugged needle or something else.

[todehnal]

Are the new floats that you are getting effected by the bulletin? If so, a true solution to this float issue could be a long time coming, and I can see a bunch of airplanes flat grounded before this is over. It may be time for an alternative fuel distribution system. I wonder if there is anything out there that will work for us??

Tom

[cactusman]

Originally Posted by f1rocket

The question now is "What to do now?". There's no replacement parts designated and as you've noted, the test kits aren't even out there yet. I suspect I have a bad float as well as I get a whiff of gas occasionally, but I don't see a point in tearing everything apart waiting months for parts to come. Do you replace the float with another similar float until the new ones are designed?

Yep - the replacements are subject to the same 25 hrs/60 day check.

No ETR on the new ones as yet.