Mmmmm Carb Floats... And a request for opinions..

[amcboy]

OK not being a total nebbish at rebuilding carbs, I went and rebuilt the carbs.

One float was, ahh, nearly sunk, and installed upside down...

So I re-installed it right side up and super glued along the leaky seam after purging the gas.

Tuned up excellent.

Drove home from work, and used 1/4 tank of gas to go 12 miles.

Black clouds and gas everywhere, like both floats stuck open. (or sank...)

Sooo, I called TRF to get new seals and floats.

Floats are NLA from TRF! Apparently the current crop of floats is crap.

Sooo, I orderd a set from VB (rolling the dice).

Now, I think the floats might be alright after all, I might have set them at the wrong height.

I used the Buckeye Triumphs settings of 0.630 to 0.670 inches.

I'm wondering if the Haynes settings of 0.725 to 0.787 inches is more correct..

If the floats are too high then the carbs will gush. The valve never fully closes, or closes while fuel is covering vent holes, etc.

I'm looking for advice on where to set the !@#%^#$ things.

Will disassemble the carbs tomorrow.

Opinions?

 

[poolboy]

AMCBoy, I've never seen anything close to the .725 in. that you found in Haynes. My Haynes says 16-17mm.
I have mine set to .627 inch.
The float needle valve itself may be causing your problem: not unheard of.
The bottom of the floats are basically flat; the top surface is kind of a "split level". That is when the carbs are in their natural position.
Do you think that the super glue is gasoline resistant?. Might have sprung a leak again?
You can spin the engine w/o starting and look at the jets to see if fuel flows up them with every stoke of the fuel pump, for a quick check.
And, if you just remove the fuel lines, the nipple gives you a straight shot at the needle valves with carb cleaner if you think that might help.

 

[KVH]

The floats were a frustrating part of my engine work last year.

First, I needed a fuel filter badly and kept assuming that I had a float needled problem when it was actually dirt in the lines--tiny specs are big enough. A fuel filter was important.

Second, that measuring bar routine described in the manual to adjust the float height was an impossible waste of time. I just set them back to the way they had been (I had to bend the forked jet lever return back to where it was).

Third, I had a new set of Grose-Jet needles, and had to toss them out as well because the original needles worked better and I can't explain why.

I'm being totally unhelpful, and I'm sure I just didn't know enough about the task, but the message for me was to proceed with caution in messing with floats that have been sealed inside a steel jar and working fine for forty years.

There are plenty of stories of bad floats and how they were fixed, but I wouldn't be able to tell one.

 

[DrEntropy]

Re: Mmmmm Carb Floats... And a request for opinio

THE Parts source: <span style="font-weight: bold">Joe Curto!</span>
As for leaky ones, never tried SuperGlue but HAVE tried other stuff. Anything that works is so heavy it changes the displacement of the float and messes up the level where it shuts the needle valve.

Gross(e) jets are junk, IMO. Viton tipped ones are as "fancy" as you need to get.

 

[amcboy]

Re: Mmmmm Carb Floats... And a request for opinio

Well I'll have a full report once I get them apart...

Thanks for the .02 though!

 

[amcboy]

Re: Mmmmm Carb Floats... And a request for opinio

Well, the super glued one wasn't leaking.

The other one was.

Both were in upside down... When I disassembled, each carb had one installed 180 from the other...

So I guessed from looking at the pictures.

Musta been tired. (Now)Its easy to see the metal flange is on one side only...

So I replaced them both.

Also replaced the bypass valve diaphramages.

Mighty crusty when I rebuilt, and the new ones from VB came with all the gaskets!

Tomorrow I'll install and report. Hopefully this will fix the falderal!

Oh, and I've never had super glue fail on gas (nitro) powered model aircraft...

 

[BobbyD]

Re: Mmmmm Carb Floats... And a request for opinio

Setting float heights with that little cardboard template is a PITA. Check out the aluminum template that Frank Fischer has made up. Very accurate and priced right.

You see his stuff here: https://tr6.danielsonfamily.org/FrankFisher.htm

NFI.... he's justs a great guy making some cool stuff to help us out

 

[amcboy]

Re: Mmmmm Carb Floats... And a request for opinio

I used my trusty 'ol Starrett calipers...

 

[amcboy]

Re: Mmmmm Carb Floats... And a request for opinio

Well, after the install and tune, all is well in the TR-6 until the next thing goes foom.

Looks like the sunken float in the front carb gooshed gas all over the rear carb and that is why I thought both were leaking.

So:

Floats right-side up, check.
Gaskets tight, check.
Tuned to an exacting standard, check.

Motorvatin' in the 70deg. sun!

 

[DrEntropy]

Re: Mmmmm Carb Floats... And a request for opinio

WooHoo!!!

We won't be discussin' upside down float installation methods then I guess?

 

[poolboy]

Re: Mmmmm Carb Floats... And a request for opinio

amcboy, you're not the first person or the last to install the floats bottom side up.
And although you didn't ask, I have found a good setting for the tension on the TBV to be 6 to 7 turns CCW from fully CW.
Too much tension and the valve won't open; too litle and the valve won't seat 100% of the time.