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Carburetor problem I can not fix angry smiley
Posted by: red64vair ()
Date: September 15, 2020 08:37PM

I have two rebuilt carburetors from a well known vendor that I can not stop from dribbling. Installed on a 145 cu engine that idles badly because some fuel is dribbling then when I try to increase engine speed much fuel dribbling and engine spits fire back thru carburetors killing the engine. The carburetors are not overflowing. I have lowered the float level to 1 1/8, that did not help so I lowered to 1 3/16 still dribbled. Each time I lowered the floats I ran the pump to fill the bowl then removed the top and the fuel level had lowered. I removed the carburetors again and checked that all passageways were open and I could not find anything wrong. I had several spare carburetors so I cleaned a pair up, inspected them thoroughly, installed needle and seat, .052 jets, accelerator pumps and set the float level to 1 1/8. The engine runs fine with no sign of dribbling.

The engine is a 145 CU. The rebuilt carbs have the enrichment valve so they must be 65 or 66. The casting #7031653 is not in Bob Helt's Rochester book. Could they be for something other than a Corvair? The carburetors I rebuilt were from a 64 engine without enrichment valves.

Larry Blaylock
Saltillo, Mississippi
64 convertible
66 customized Corsa coupe


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Re: Carburetor problem I can not fix angry smiley
Posted by: tboltkc ()
Date: September 15, 2020 09:27PM

Have you talked to the supplier?

Of it were me I'd try to return those and just use the ones you did that work.

-Travis


'65 Corsa; '63 Convertible; '62 Wagon; '65 4 Door
Heart of America Corvair Owners Assocation (Kansas City, MO)
[www.hacoa.org]

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Re: Carburetor problem I can not fix angry smiley
Posted by: MattNall ()
Date: September 15, 2020 09:48PM

There are 2 sizes of inlet valves! Make sure they have the smaller ones.

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: Carburetor problem I can not fix angry smiley
Posted by: alphasud ()
Date: September 15, 2020 09:53PM

Too much fuel pressure causing the fuel to push past the needle and seat.

David North Idaho
1965 Corsa Turbo converted to 140
1971 Super Beetle with 2.5L Subaru engine
1965 Corsa mid engine project
1973 Mercedes 280 project

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Re: Carburetor problem I can not fix angry smiley
Posted by: TerribleTed ()
Date: September 15, 2020 10:09PM

Set the floats to a height of 1 13/64 per the shop manual and make sure the fuel pressure is not above 5PSI 3-4 is ideal. should not dribble or flood after that unless the dribble is from warped venturi clusters.

---------------------------------------------------------------------------------------------------------

Avid Corvair hobbiest since 1984.
I have personally performed ground up restoration on over 20 Corvairs.
I currently work full time at restoring and repairing Corvairs.
Located in the Atlanta Georgia area.
[www.facebook.com]

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Re: Carburetor problem I can not fix angry smiley
Posted by: autocomman ()
Date: September 15, 2020 10:21PM

Ditto, check that fuel pressure. Dribbeling is usally leel in teh bowl too high from the pump pushing right past the needle and seat

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Re: Carburetor problem I can not fix angry smiley
Posted by: red64vair ()
Date: September 15, 2020 10:24PM

Supplier has agreed to accept return. Inlet valves .082 in both carbs, fuel pressure a little high at 5 LB but does not overcome the inlet needle in the carbs I rebuilt. My carbs and the rebuilt ones both have the small floats with the helper spring.

Larry Blaylock
Saltillo, Mississippi
64 convertible
66 customized Corsa coupe


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Re: Carburetor problem I can not fix angry smiley
Posted by: American Mel ()
Date: September 15, 2020 11:46PM

red64vair Wrote:
-------------------------------------------------------
> I have two rebuilt carburetors from a well known vendor that I can not stop from dribbling. . . . . . . . . . . . . . . . . . . . .



Uh, Canine Carbs, by any chance ? ? ? eye rolling smiley

-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
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.
Have; '66 Monza Coupe - 140, 4-spd. Daily driver beater
'67 Monza Vert. - 140, 4-spd. Daily driver beater
'67 A/C Moredoor Monza
Have had; '61 Monza coupe, 80hp, PG
'62 Monza Wagon, 4spd.
'63 Spyder,
'65 Corsa
.
non-vair
'04 Dodge Cummins Quad Dually, approaching 400K
'03 Honda Del Sol
17'Terry

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Re: Carburetor problem I can not fix angry smiley
Posted by: autocomman ()
Date: September 16, 2020 12:10AM

How do you know they are ont overcoming the needle and seat? you cant see them or the actual float level when its running...

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Re: Carburetor problem I can not fix angry smiley
Posted by: RobertC ()
Date: September 16, 2020 12:47AM

Is the spring installed correctly?

The spring should be on the outside of the inlet valve. "Arms" of the spring at about a 90 degree angle.

Also, I would check the oil and most likely change it.



Edited 1 time(s). Last edit at 09/16/2020 12:56AM by RobertC.

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Re: Carburetor problem I can not fix angry smiley
Posted by: dryenko ()
Date: September 16, 2020 04:35AM

The small anti flow needles in the high speed enrichment circuit well under the cluster may be missing.

Bob C aka Dryenko
Dobson, NC 27017

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Re: Carburetor problem I can not fix angry smiley
Posted by: JimBrandberg ()
Date: September 16, 2020 06:53AM

I find this trouble more than I care to admit and wish I had a simple solution. I've spent hours and sometimes have to move along to a different carburetor base from frustration. I didn't used to have this much gray hair.

It's usually just on one side so careful consideration of starting from the same throttle plate position on both sides helps. I often do this on the bench, going 1.5 turns down from contact and then adjusting the left swivel link when installing. Sometimes one turn less on the offending carb helps.

Originally there were EM and LM sized inlet seat holes. The ones often available are bigger still. I bought a supply of smaller ones from Wolf. I too could not understand why this would make a difference but sometimes it does. I always thought as long as the float bowl wasn't overflowing it was good but I've had to change my thinking with the #&*^%#$! dribbling. Same with fuel pressure.

Same with float level, sometimes it helps to lower the fuel level until it stops.

Sometimes I suspect the high speed enrichment circuit but I've had trouble with EM carbs dribbling too.

There's been other discussions if you search.

I keep reading everything I can find and would be happy to read more. It hurts my pride to suffer defeat in this area. I've wasted many frustrating hours in the last few years. I just don't remember it being a problem years ago.

Jim Brandberg
Isanti, MN
CorvairRepair.com



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Re: Carburetor problem I can not fix angry smiley
Posted by: corventure Dave ()
Date: September 16, 2020 08:06AM

Oh that venturi drip!!!!
The carburetors need to be assembled properly. I have also ran across far too many defective float valves, being one primary suspect.

Also... the float compensator spring has to be adjusted properly. It needs to slightly support the float. Spring tension should be so that the float is just about weightless with the carburetor held in the upright operating position. The spring should not hold the float valve closed. Nor should the float push the spring down to it's float drop position.
This adjustment has solved many carburetor-venturi drip issues.

Corventure Dave

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Re: Carburetor problem I can not fix angry smiley
Posted by: RexJohnson ()
Date: September 16, 2020 09:01AM

If it is dripping out of the cluster and the float level is fine then the idle circuit is probably plugged. The carb is trying to work so the fuel is coming out of what is open, the main metering circuit. I worked with some rebuilt carbs from a well know vender and they would not idle same problem. I switched out the carbs and the problem was gone. I had taken them apart 2 or 3 times and you couldn't see anything wrong with them. I talked to the vender and told him what was happening and what I had done to try and fine the problem. So he sent another set and the engine ran great.

RJ tools
Salem,Oregon

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Re: Carburetor problem I can not fix angry smiley
Posted by: Carburetor ()
Date: September 16, 2020 09:04AM

What Corventure Dave said - I did that and got rid of a nagging dribbling cluster.

FWIW, what I did to is set the float drop to the spec (per Bob Helt's book, I can't recall the exact measurement at the moment) without the assist spring, and then with the assist spring I aimed for 1/32" less float drop. I did that to simulate the "weightlessness" that Dave mentioned the same across all four carbs.

Jim C.
Chesterfield, MI

1966 Monza convertible (140 / PG)
2017 Chevrolet Trax (daily driver)
2017 Chevrolet Volt (wife's ride)


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Re: Carburetor problem I can not fix angry smiley
Posted by: TerribleTed ()
Date: September 16, 2020 11:23AM

American Mel Wrote:
-------------------------------------------------------
> red64vair Wrote:
> -------------------------------------------------------
> > I have two rebuilt carburetors from a well known vendor that I can not stop from dribbling. . . . . . . . . . . . . . . . . . . . .
>
>
>
> Uh, Canine Carbs, by any chance ? ? ? eye rolling smiley

canines evolve from wolves right?

---------------------------------------------------------------------------------------------------------

Avid Corvair hobbiest since 1984.
I have personally performed ground up restoration on over 20 Corvairs.
I currently work full time at restoring and repairing Corvairs.
Located in the Atlanta Georgia area.
[www.facebook.com]

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Re: Carburetor problem I can not fix angry smiley
Posted by: American Mel ()
Date: September 16, 2020 11:59AM

TerribleTed Wrote:
-------------------------------------------------------
> American Mel Wrote:
> -------------------------------------------------------
> > red64vair Wrote:
> > -------------------------------------------------------
> > > I have two rebuilt carburetors from a well known vendor that I can not stop from dribbling. . . . . . . . . . . . . . . . . . . . .
> >
> >
> >
> > Uh, Canine Carbs, by any chance ? ? ? eye rolling smiley
>
> canines evolve from wolves right?


All of the "dog-like" mammals fall under the Canidae grouping.
Mammalia, Theria, Eutheria, Carnivora, Caniformia, Canidae, Canis

Canis(Canine) is the genus that moderns dogs(Canis Lupis Familiaris) come from.
Canis includes: Domestic Dog, Coyote, Jackals, and Wolves.
Wolves(Canis Lupis) are older, more primitive, and less developed than Modern Dogs.

-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
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.
Have; '66 Monza Coupe - 140, 4-spd. Daily driver beater
'67 Monza Vert. - 140, 4-spd. Daily driver beater
'67 A/C Moredoor Monza
Have had; '61 Monza coupe, 80hp, PG
'62 Monza Wagon, 4spd.
'63 Spyder,
'65 Corsa
.
non-vair
'04 Dodge Cummins Quad Dually, approaching 400K
'03 Honda Del Sol
17'Terry

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Re: Carburetor problem I can not fix angry smiley
Posted by: 66vairman ()
Date: September 16, 2020 07:35PM

Carburetor Wrote:
-------------------------------------------------------
> What Corventure Dave said - I did that and got rid of a nagging dribbling cluster.
>
> FWIW, what I did to is set the float drop to the spec (per Bob Helt's book, I can't recall the exact measurement at the moment) without the assist spring, and then with the assist spring I aimed for 1/32" less float drop. I did that to simulate the "weightlessness" that Dave mentioned the same across all four carbs.

Yes the "new" reproductions float spring tension is too great.

It is getting to the point were some carburetors just don't work when rebuilt due to warped parts and corrosion in the inner passages.

One thing to check is that BOTH floats are on the same plane.

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Re: Carburetor problem I can not fix angry smiley
Posted by: JimBrandberg ()
Date: September 17, 2020 06:15AM

I've printed off the float spring discussion above as a good reminder. I suffer from CRS.

Jim Brandberg
Isanti, MN
CorvairRepair.com



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Re: Carburetor problem I can not fix angry smiley
Posted by: corventure Dave ()
Date: September 17, 2020 07:47AM

Also Venturi cluster warpage. This is more of a vacuum leak, than a drip issue.
But good to check.

Covered here on... "Often overlooked on carburetor rebuild".

Corventure Dave

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