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Checking carb floats

tomkk

tomkk

Well Known Member
I remember seeing a short video about how to easily remove the float bowl but I'll be darned if I can find it now. Does anyone remember where it was?
 
tomkk said:
I remember seeing a short video about how to easily remove the float bowl but I'll be darned if I can find it now. Does anyone remember where it was?
Click to expand...

Tom, have you gotten the "new" floats? I had mine changed out recently at Lockwood - my understanding is that this fulfills (eliminates) the SB that requires inspections. That said, it seems prudent to "trust but verify"....

TB
 
AZLeeJay said:
Roger Lee has a video on youtube that may be helpful, he demonstrates the procedure on a Flight Designs aircraft so its a little different, I find that removing the airlifted and loosing the clamp attaching the carb to the intake and actually pulling the carb back allows us in the RV12 to remove the bowl and check the floats. I'll bet that the rotax owner site also has something.

https://youtu.be/XBT-yQ_X3N8
Click to expand...

Yup, that's the one I wanted, thanks. I knew it was there, just couldn't find it.
 
mturnerb said:
Tom, have you gotten the "new" floats? I had mine changed out recently at Lockwood - my understanding is that this fulfills (eliminates) the SB that requires inspections. That said, it seems prudent to "trust but verify"....

TB
Click to expand...

Yeah, I was one of the lucky ones who got the new floats early - got mine back around the middle of March and installed them before the my first engine run. Unfortunately, I'm getting fuel leakage out of the air filter on my right carb when the fuel pump is running. The floats are the first things I was going to check. I only have 25 hrs on the engine. It's been running great until yesterday. Maybe the new floats don't really correct the original problem after all, we'll see.
 
It could also be a tiny contamination particle under the needle valve... not totally uncommon on a brand new installation. Sometimes contaminants that are down stream of the gascolator (inside hoses, etc.) get flushed out and cause problems. Usually wont happen again after it is cleaned out.
 
Thanks, Scott, that was my other thought. When I dropped the bowl, though, there wasn't any sign of contamination but one of the floats (one of the new ones with two dots on them) was almost totally sunk. Weighed in at 5.5 grams vs 3.2 for the other.

Lockwood is sending a replacement that will get covered under warranty but I'm a bit disappointed that one of the new floats failed after less than 25 hrs of operation. Oh well ...
 
I replaced my carb floats with the new ones from Lockwood about 30 hours ago. The engine was running fine with the old floats. But now I am experiencing a fuel odor after takeoff and during landing. I cannot find any evidence of gas leakage in front of the firewall or behind it.

There is no odor at all when parked on the ground. I am beginning to suspect the "new" floats might not be as buoyant as the old ones.

It might not be relevant, but the air filters appear to be turning white, not dark as the red oil captures the dust in the air.

I'm going to remove and weigh the floats per the Rotax SB and see what I get.

Mitch
N2ET, flying since March
 
Fuel odors can be difficult to find, especially if they are in an airflow stream. I even ran mine with the cowl off trying to locate mine. I did not see the source at first, but I did notice a fine mist in a very small area on the windshield. Further examination identified a leak at the banjo fitting and return line. That line takes a very tight 90 degree turn at the banjo fitting before heading back to the fitting on the firewall shelf, and with no clamp on that hose, it is very susceptible to a leak. The airflow over the top of the engine will carry that tiny amount of fuel away, leaving no evidence. I added a clamp to that hose, at the banjo fitting, and my problem was solved. Hope that helps............Tom
 
I just had to replace one of my floats (see previous posts in this thread). My symptoms of a bad float were very obvious once the float was really bad: engine stumbled badly at most anything very much above idle RPM. I could also see fuel leaking out of the air filter with the engine stopped but the electric fuel pump running. In retrospect, there were slight rough running symptoms well before it progressed that far, I just wasn't familiar enough with the engine to recognize them for what they were. I know better now ...
 
I pulled all the floats and weighed them. Left carb: 3.0g, 4.1g....Right carb: 3.2g, 3.3g. Lockwood is sending one float tomorrow to replace the 4.1 gram one. I have to submit the long form for the warranty and pay up front.

Hope this fixes it.

Mitch
N2ET
 
Mitch757 said:
I pulled all the floats and weighed them. Left carb: 3.0g, 4.1g....Right carb: 3.2g, 3.3g. Lockwood is sending one float tomorrow to replace the 4.1 gram one. I have to submit the long form for the warranty and pay up front.

Hope this fixes it.

Mitch
N2ET
Click to expand...


Wow!! Now that is scary! You must have late production floats, since you just replaced them 30 hours ago, and now, again, one is bad. Please take a look, make sure that it has the new markings, and let us know.
And I thought that we had all of this Bing Carb **** behind us..............Tom
 
Hi Tom,
Yes, they are the replacement floats and I'm not sure that that little over the "limit" is causing my fuel smell. At least a new one is on the way.

Everything else on the engine is tight. I ran the electric fuel pump for 15 minutes and could not find any hint of a leak anywhere.

Fingers crossed.

Mitch
N2ET
 
Mitch, amazingly, running the electric pump did not show my return line connection leak either. It took running the engine with the top cowl off to catch it. Even then, it was very subtle; nothing but a little fine mist on the canopy. Good luck. Hope the new float fixes your problem, and do let us know...............Tom
 
carb floats

Last week developed a problem with rpm drop on run ups with excessive (300 drop) numbers on the A ignition. Replaced badly loaded black velvet plugs and run up was fine. Flew one hour and OK. This week problem came back.Checked out ignition modules and they appear to be ok after various tests. Last attempt at test run up was so rough I shut engine down w/o getting the numbers. Altho I did the carb check during run ups (full choke) there was no sign of carb issue. Suggestion by tech help says look at the carb floats. I did not have an engine or carbs in the serial numbers that were spelled out for float issues so did not worry with the float checks last year, and had no problems. However last October when I sent carbs to Lockwood for dis assembly and check at 200 hours (actually 270 hrs) they installed the new floats. I won't be able to work on carbs for a few days but will drop the bowls and etc. soon. Will be interesting to see what I find. Any others out there have current problems with floats installed in last six months?
Dick Seiders
 
carb floats

Yes, Now completing my first condition inspection and found the floats on the right carb at 7.1 grams. I ordered and installed two new floats which each weighed 2.7 grams before installation.

As of now, I have replaced 3 of the 4 "new" floats that I installed under the SB.

Total time on the engine is 98 hours.

Mitch Garner

PS: I heard a rumor that Marvel Schebler was making some trial floats for either Rotax or Bing. Really hope it's true.
 
carb floats

Mitch, 3 bad out of four sounds like suppliers are getting rid of old floats OR Rotax has a far bigger problem (as do we) than first believed. I mean it's been about a year since it became an issue. Seems to me there shouldn't be any bad floats any more. Have you looked at yours to see if the new marking is there to identify the new from the old? Is this kind of performance typical or are you just having bad luck? Surely there are others having this experience considering the frequency you have seen ?

Dick Seiders
 
Hi Dick,
I have not had any "runnability" problems but just the odor when the floats are or become overweight. All the floats that I have installed have the identifying dents. Hopeing that it is fixed now. I just can't believe Rotax can't find floats that FLOAT!

My original floats were fine....shoulda kept them. Mr. Busch is right; Don't fix what isn't broken.

Mitch Garner
 
Has anybody gone directly to the Bing distributor at bingcarburetor.com to get parts?

I'm wondering if there is an advantage over our more traditional aviation vendors?

I will be doing the 500 hour checks next year and will need at least the rubber components so I am interested in what other owners have to say about parts suppliers.
 
I have recently had a dimpled replacement pair of floats fail the weight test. I am waiting to see if ROTAX will honor the warranty on these failed dimpled floats. I like to characterize ROTAX's aftermarket warranty policies and performance as "bizantine".
 
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