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Re: Engine trouble on takoff

Posted: Sun Jun 02, 2019 10:45 pm
by Warmi
3Dreaming wrote:Get rid of the cork gasket! Actually they don't sell the fiber gasket anymore. The new gasket is a rubber type material. They changed sometime last year.
yeah, that’s what I noticed ...

https://www.leadingedgeairfoils.com/gas ... -carb.html

It is rubber like and pretty expensive too :D. - I am wondering if using white lithium grease still applies here as well ?

They also have new floats .... https://www.leadingedgeairfoils.com/flo ... -6600.html. .... $150 a pair, slightly more expensive with every revision :D

Re: Engine trouble on takoff

Posted: Mon Jun 03, 2019 8:34 am
by 3Dreaming
The fiber gaskets are fine, you just can't buy them anymore. At least not from Rotax.

Re: Engine trouble on takoff

Posted: Mon Jun 03, 2019 8:18 pm
by akroguy
FastEddieB wrote:I had an issue when I used a thin layer of silicone gasket sealer to hold the float bowl gaskets in place. DON'T DO THAT!!!

The silicone can react with the gas and turn to jelly:

Image

Pretty sure this is what caused some very rough running over wooded terrain in S GA, leading to me declaring an emergency. Fortunately it smoothed out in a minute or so and all was well.

I learned that just a touch of grease is the ticket to hold the gaskets in place. When gas hits grease, it just harmlessly dissolves.

Lesson learned!

Been there, done that! Used red RTV on a carb fitting on an O-360. Ran fine for over 40 hrs (the test phase on my RV8) then a bit of the goo let go and stuck the float. Carb went full rich and the engine would not burn it at 10,000'. Glided down to the best dead stick landing ever to an airport below me. Must have been living right. Since that potentially disastrous lesson, I use fuel lube on gaskets with no problems.

Re: Engine trouble on takoff

Posted: Sat Jun 15, 2019 10:50 am
by Warmi
drseti wrote:It's true that the service bulletin calls for under 7 grams per pair (I think), so your 6 grams meets the soec. I still prefer to weigh them individually, and match pairs so they push up symmetrically on the fuel flow metering mechanism. Thus, the 2.7 grams each that I typically see.
......
So I ordered the latest set of floats and the latest rubber-like gaskets - installed the whole thing with a bit of white lithium grease and everything seems to work fine.

Interestingly , the latest floats ( marked R) weight about 3.23 each right out of the box while the old ones were around 2.9 or so ... I weighted both , old and new and there is definitely a difference - the new ones are heavier :D

Re: Engine trouble on takoff

Posted: Sat Jun 15, 2019 12:32 pm
by Wm.Ince
I wish Rotax (Bing) would stop screwing around with these foam-core floats and go to metal, once and for all. At least, applicable for aircraft applications. Over the last 7-8 years, how many iterations of float changes have we had?
Enough is enough.

JMTC

Re: Engine trouble on takoff

Posted: Sat Jun 15, 2019 1:30 pm
by ShawnM
Wm.Ince wrote:I wish Rotax (Bing) would stop screwing around with these foam-core floats and go to metal, once and for all. At least, applicable for aircraft applications. Over the last 7-8 years, how many iterations of float changes have we had?
Enough is enough.

JMTC
I agree, they've been chasing their tail long enough with these damn floats. Ditch the foam and go with plastic or metal and never worry about them again. I've been through 3 pairs in 6 years and they ain't getting any cheaper either.

Re: Engine trouble on takoff

Posted: Sat Jun 15, 2019 2:50 pm
by FastEddieB
I’ve seen soldered metal floats fail as well.

Re: Engine trouble on takoff

Posted: Sat Jun 15, 2019 3:46 pm
by Wm.Ince
FastEddieB wrote:I’ve seen soldered metal floats fail as well.
At an equivalent rate as these foam core floats? I seriously doubt that.
I personally have never witnessed that, even in the era of automotive carburetors (Holly and Rochester). I don’t recall ever seeng a factory recall of either of those metal floats. I am not implying that never happened though.

Re: Engine trouble on takoff

Posted: Sat Jun 15, 2019 4:43 pm
by 3Dreaming
Just as a side point. Marvel Schebler the standard carburetor used in many light aircraft has went through at least 3 or 4 different float designs and materials since I have been an aircraft mechanic.