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EM Carburetor Float Needle Style
Posted by: MonzaJPD61 ()
Date: October 23, 2017 05:45PM

Thinking about switching back from the soft tip float needles to the original all-stainless float needles on my 61. Anyone tried this and can share results?

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Re: EM Carburetor Float Needle Style
Posted by: American Mel ()
Date: October 23, 2017 05:50PM

Many people here use the little ball valve that Clark's sells

.
-----------------------------------------------
WA. state, 1 mile south of the Canadian border,
I am not at the end of the world, but you can see it from here.
'66 Monza Coupe - 4spd, 140 Daily driver beater
'67 Monza Vert. - PG, 140 Daily driver beater

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Re: EM Carburetor Float Needle Style
Posted by: MonzaJPD61 ()
Date: October 23, 2017 05:57PM

I tried those pricey rascals and did not have a good experience with them.

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Re: EM Carburetor Float Needle Style
Posted by: MattNall ()
Date: October 23, 2017 06:53PM

Hard tips last forever!!





MODERATOR
Sea Mountain, between Charleston Harbor and Coos Bay! SW Oregon Coast
Click HERE for My Website...Click HERE for My TechPages!
..............................110-PG.................................................Webered-Turbo

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Re: EM Carburetor Float Needle Style
Posted by: vairmech ()
Date: October 24, 2017 04:53AM

Yes, the hard tips last forever but the seat takes a pounding, literally! With the steel needles the seats will wear and you will have a maintenance item called float adjustment every so often.

Why do you want to NOT use the Viton tipped needles?

Ken Hand
Handy Car Care
248 613 8586

Vairmech@aol.com

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Re: EM Carburetor Float Needle Style
Posted by: RobertC ()
Date: October 24, 2017 09:02AM

Agree no problems with viton tipped needle.

You do need to check the mating surface in the seat.

Over the (recent) years, I have found a couple seats where the mating surface of the seat is flawed - and tossed them in the trash.

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Re: EM Carburetor Float Needle Style
Posted by: MonzaJPD61 ()
Date: October 24, 2017 04:21PM

Main reason is inconsistent bowl fuel levels and built in need to periodically replace soft tip needles.

It's hard to believe the s.s. needles wearing out the seat to the point it's not serviceable. Have some of you really experienced this?

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Re: EM Carburetor Float Needle Style
Posted by: vairmech ()
Date: October 24, 2017 04:30PM

The answer to your question is yes and no. I have had to reset the float levels many times on one carb because of seat wear, it never became unserviceable though, it would just start flooding at some point.

Ken Hand
Handy Car Care
248 613 8586

Vairmech@aol.com

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Re: EM Carburetor Float Needle Style
Posted by: RobertC ()
Date: October 25, 2017 12:59AM

MonzaJPD61 Wrote:
-------------------------------------------------------
> Main reason is inconsistent bowl fuel levels and
> built in need to periodically replace soft tip
> needles.
>

What does periodic mean? As in how long? Months / Years / Miles?

The soft tips in mine have lasted for years.

It is true there is a slight groove in the tip when replaced, but have experienced no flooding / etc issues.

Maybe you should inspect the seat like I suggested above...

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Re: EM Carburetor Float Needle Style
Posted by: Ratt643 ()
Date: October 25, 2017 06:49PM

I have rebuilt alot of Corvair carbs. I tried the Clarks check ball seats and had nothing but flooding problems. Never had any trou le out of mine or customers carbs using the viton needles. Have you checked you floats to see if it might have a pin hole allowing gas to cause the float to sink and flood tbe carb. Im not sure how much this plays but do you have the spring on the floats as well?


1964 Monza Coupe

Maryville, TN
U.S. 129 The"Tail Of The Dragon"

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Re: EM Carburetor Float Needle Style
Posted by: MonzaJPD61 ()
Date: October 25, 2017 08:21PM

I did check my floats and they are ok. I believe a contributor to my problem has been using the seats supplied with almost all currently produced kits for the Rochester H carbs. According to Bob Helt's book, my 61 takes small diameter hole seats and most all those seats are large diameter internal passage for later models. The 61 carbs didn't have the float springs.

So, I just finished redoing everything as close to original spec. as I could on both carbs and have it all reassembled and put back on the car. Just waiting until after work tomorrow to set idle, adjust mixture and balance and synch.

To address the throttle shaft wear I found, while I had everything apart, I installed the Clark's throttle shaft sealing O-rings. I'm pretty happy with how that went on.

Fingers crossed.



Edited 1 time(s). Last edit at 10/25/2017 08:25PM by MonzaJPD61.

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Re: EM Carburetor Float Needle Style
Posted by: vairmech ()
Date: October 26, 2017 04:33AM

There is a tech article in the Corsa Tech Guide about that very thing!

Over the years there have been 3 different needle and seat hole sizes. The very small hole needle, about .070", and seat should NOT be used as under full throttle operations the needle and seat cannot flow enough fuel to feed the carb and can actually starve the engine. Yes, this has happened to me! The next size, about a .150", and the most common now is actually the best combination and the most correct. There was also a very short lived large bore opening and is still used in the turbo carb. That size has flooding issues and can't control the fuel flow especially at higher pressures. That is why the turbo carb is so sensitive to fuel pressure!

My size numbers may be off as it has been a while since I have measured or looked at the article but you get the idea of what is going on.

Ken Hand
Handy Car Care
248 613 8586

Vairmech@aol.com

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Re: EM Carburetor Float Needle Style
Posted by: steve c goodman ()
Date: October 26, 2017 07:28AM

vairmech Wrote:
-------------------------------------------------------
> There is a tech article in the Corsa Tech Guide
> about that very thing!
>
> Over the years there have been 3 different needle
> and seat hole sizes. The very small hole needle,
> about .070", and seat should NOT be used as under
> full throttle operations the needle and seat
> cannot flow enough fuel to feed the carb and can
> actually starve the engine. Yes, this has happened
> to me! The next size, about a .150", and the most
> common now is actually the best combination and
> the most correct. There was also a very short
> lived large bore opening and is still used in the
> turbo carb. That size has flooding issues and
> can't control the fuel flow especially at higher
> pressures. That is why the turbo carb is so
> sensitive to fuel pressure!
>
> My size numbers may be off as it has been a while
> since I have measured or looked at the article but
> you get the idea of what is going on.

Steve sez: Good memory Ken. I think John Martin wrote the
article but I don't recall the date.

I started a silly and useless practice in the late 90s of
saving the brass parts from the carbs I was rebuilding.

When the article appeared in the COMMUNIQUE I dug into
the cans of old float valves and did a "show 'n tell"
for the club meeting. I still have the display and am
looking at it right now. I found hole diameters from
.053" to .116". I am certain there are more too but I
stopped there, I figured a .060" span would be enough.
FWIW these are all from different kit manufacturers
and some from years past.

What is the end result of these different diameters? As
Ken states above it has to do with fuel pump pressure
and volume plus engine demand. We know that the
"one size fits all" of todays kits works in either early
or late engines under normal use. I just used number drills
to check Clark's part, it is .078". These numbers are for
Roch carbs only, NOT the YH.

best wishes, Steve
Rear Engine Spec. Inc. Golden, Colo.

1962 spyder 3.0L turbo---1965 Crown V8
1967 monza 110/4---1968 monza 110/4
1971 amante gt 110/4
CORSA/RMC/PPCC

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Re: EM Carburetor Float Needle Style
Posted by: MonzaJPD61 ()
Date: October 27, 2017 12:20AM

Thanks Steve

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