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Carburetor Bowls on the 912ULS

backcountry

Well Known Member
I’m having problems with the finish on the inside of the carburetor Bowls flaking off. Sometimes the engine goes very rough and I have to reduce power and it’s not enough to stay in the air sometimes. Then I pull the bowls from the carburetors find this flakes in the bottom of the bowls and I clean them up and the engine runs fine again. The problem is it returns again as the flaking continues.
The finish on the inside of the bowls are bubbled up as it looks to be corrosion underneath the finish. My guess is it’s caused by ethanol fuel.
I’m looking for good source to replace these bows with new ones as I’m afraid to use the old ones any longer.
 
I've got some 9 years / 1,250 hours on my RV-12 ULS using California 91 mogas with @10% ethanol about 95% of the time. No signs of flaking inside the carb bowls. Replacement bowls can be had at LEAF, Aircraft Spruce, etc. The new bowls should have the added enhancement of having sealed float locator pin bosses.
 
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Must be ethanol fuel combined with not having plane flown for long periods of time ( at least that’s what I was told )

My 2012 carb bowls appear to be pretty clean but I don’t use ethanol fuel ..
 

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I have put >350 hours on the Rotax 912 ULS in my RV12 since first flight in 12/2020. I've been using all brands of 91-93 octane w/ ethanol (although predominantly Costco 93). The carb bowls always look fine (latest CI was done last month).
Perhaps the best thing to do is not let ethanol laden gas "sit" for any extended period of time?
It may not be feasible to some (that aren't retired?!), but try to fly a lot (weekly?) or drain & replace the fuel with fresh (use it in your car).
 
Yes, the one pictured above looks great.
I started flying mine late 2017 and have 260 hrs mostly local weekly flights. The plane is hangered here at my home south of Houston.
 
Buy a new set from Lockwood Aviation, they have a newer type that does not have the float pins going all the way through the bowl, I had a pin come loose and had a lot of fuel pouring out, perhaps the newer floats won't corrode out as fast, I think they cost about $120 each.
 
Just some feedback.
I ordered new carburetor bowls. They no longer offer the silver bowls. The new ones are black, and the gaskets are rubber.
I guess they must have had problems are they would not have changed the finishes.
 
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