I want to crush this Carburetor!!

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65corvairbuggy
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Joined: Fri Jul 03, 2020 9:44 am

I want to crush this Carburetor!!

Post by 65corvairbuggy »

So I have a little issue maybe some of yall can help me with. Little background I have a 65 110 in a fiberglass buggy that I pulled out of my grandfathers barn after sitting for a little over 40 years. I have completely restored it rebuilding the entire engine. I just got done wiring the whole thing and have proceeded to try and fine tune the engine. I have it idling on one bank! I have checked compression and have 160 psi across the board. I said my dwell and my timing and proceeded to swap carbs. I found d the problem followed the carb. So thats fine everyone might say just buy another carb. Well i want to know what part of the carb is the issue. I have been through the idle circuit a million times. What am I missing??? From the numbers on the carb they seem to be the 68 or 69 smog carbs as they have the extra screw under the choke.

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bbodie52
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Re: I want to crush this Carburetor!!

Post by bbodie52 »

:wave: :welcome2: Welcome to the Corvair Forum!
65corvairbuggy wrote: » Fri Jul 03, 2020 11:53 am

...I have it idling on one bank...and proceeded to swap carbs. I found d the problem followed the carb... Well I want to know what part of the carb is the issue. I have been through the idle circuit a million times. What am I missing??? From the numbers on the carb they seem to be the 68 or 69 smog carbs as they have the extra screw under the choke.
I have attached a copy of the DELCO ROCHESTER - Models H, HV Carburetor Service Guide, which focuses heavily on the theory of operation of the various carburetor circuits and subsystems in your Corvair carburetors. Detailed description of the Idle Vent system and Idle system begins on page 4. Perhaps this detailed description of the idle system will increase your understanding of the idle circuit and will help with your troubleshooting and fault isolation efforts. It certainly sounds like some blockage of a portion of the idle vent/idle fuel passageways in the carburetor body that has not been successfully cleared. I'm assuming that when the engine operation and speed rises above the idle circuit and brings the main discharge nozzle and venturi into play, both cylinder banks appear to be in full operation?

You should make certain that the carburetor bodies are identical and the removable components are also identical when comparing both carburetors. Sometimes components from other model years slip into the mix during disassembly and rebuild by previous owner(s), which can impede proper operation of the intake manifold vacuum-driven idle circuits.

If chemical cleaning and air pressure blasts fail to resolve the problem, you may be faced with obtaining a serviceable used matching replacement. Clark's Corvair Parts or the Corvair Ranch may be able to produce the correct unit.

You might contact the Corvair Ranch in Gettysburg Pennsylvania. They know a lot about parts substitutions, have a large inventory of used Corvair parts and may be able to help you. Recommend you give them a call to discuss your needs...

:link: http://www.corvairranch.com/
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1079 Bon-Ox Road, ​Gettysburg, ​PA. 17325 USA
​Phone: 717-624-2805

fax us by the same number... ask us to hook up the machine

Email: findit@theranch.today

Our hours are Monday thru Friday 9 to 5, Saturday 9 to 12 or contact us for an appointment.


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:dontknow: I would like to encourage you to expand on your earlier post and tell us more about yourself, as well as about your Corvair interests and Corvair-powered buggy. (Does it use a Corvair transaxle or a Volkswagen transaxle?) Can you post some pictures? If you can provide your personal assessment of your mechanical skills and abilities, that would help a lot. Members of the Corvair Forum love to be helpful in assisting other Corvair owners with technical support and advice, but it helps a lot if we have some understanding of your technical background and mechanical abilities, your Corvair-related knowledge, etc. Helping us to know more about you will help us to write comments to you that are tailored to your needs and experience. If there is a CORSA club chapter near you, contacting local like-minded Corvair owners can add a great deal with their local support knowledge, assistance and advice. Knowing your location can sometimes suggest some possibilities.

The link below will provide you with a list of useful websites that are Corvair-related. Some of the links will lead you to an extensive technical library that will allow you to download shop manuals and other technical references in Adobe Reader format at no cost. There is also a link that will help you to locate nearby CORSA (Corvair Society of America) club chapters. You will also find a list of essential Corvair parts suppliers. Clark's Corvair Parts in Shelburne Falls, MA is the biggest and oldest Corvair supplier in the world. You will find a link that can provide you with a series of videos that amount to a tour of the Clark's Corvair Parts facilities. I think you will be amazed at the quality of the reproduction components they offer — particularly the interior carpeting and re-upholstery items. Parts suppliers such as this truly make our Corvair hobby possible.

Common and Useful Corvair Websites

:link: viewtopic.php?f=225&t=6007

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More available carburetor references...

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:link: http://www.corvair.com/user-cgi/catalog ... w_page=245

Image :link: http://www.corvair.com/user-cgi/catalog ... w_page=246
CARBURETOR TRAINING BOOKLET
All Corvair carburetors (exc. Turbo). Originally designed for training Dealer Mechanics. 28 pictures More detailed steps and theory than in a Shop Manual.
:chevy:
Attachments
DELCO ROCHESTER - Models H, HV Carburetor Service Guide.pdf
DELCO ROCHESTER - Models H, HV Carburetor Service Guide
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Brad Bodie
Lake Chatuge, North Carolina
Image 1966 Corvair Corsa Convertible

65corvairbuggy
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Re: I want to crush this Carburetor!!

Post by 65corvairbuggy »

Thanks! Thats very helpful. My name is Chris. Nice to meet you. I live in Fayetteville Georgia. I'm actually a full time mechanic lol. But this day and age all I work on is fuel injected computer controlled cars totally different Era as I am only 30 lol. Im very knowledgeable around an engine as I have rebuilt the whole thing and the carbs but that one carb is just giving me fits. I found out that if I backed the mixture screw out quite a bit that it seemed like that bank came online. Whereas the other bank sounds good at 1 1/2 or 2 turns out. I probably won't be working on it anymore more this weekend as it is the 4th but I may be able to get some time in on Sunday. Thanks a lot for the info again. I will try and get some pics up for you to take a look at

65corvairbuggy
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Re: I want to crush this Carburetor!!

Post by 65corvairbuggy »

20200621_191306.jpg

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terribleted
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Re: I want to crush this Carburetor!!

Post by terribleted »

Sounds like you have at least a partial blockage in the idle circuit somewhere. I have crushed carb bases once or twice before after trying 2-3 times to get them to idle and failing! After 2-3 tries I have always just walked over to my pile of cores and grabbed another base to clean:) The pile is smaller these days. I am in Snellville, GA . Good luck with it. Idle mixture is ideal around here at right around 1 3/4-2 turns out based on the many Vairs I have tuned carbs on.
Corvair guy since 1982. I have personally restored at least 20 Vairs, many of them restored ground up.
Currently working full time repairing Corvairs and restoring old cars.
https://www.facebook.com/tedsautorestoration/

Located in Snellville, Georgia

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bbodie52
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Re: I want to crush this Carburetor!!

Post by bbodie52 »

I am about 130 miles north of your location at the Georgia/North Carolina border, near Hiawassee.
65corvairbuggy wrote:...I found out that if I backed the mixture screw out quite a bit that it seemed like that bank came online. Whereas the other bank sounds good at 1 1/2 or 2 turns out...
Is the throttle butterfly valve facing the right way, with the notch on the same side as the idle mixture needle (Figure 4)? The description below sounds like the fuel for idling comes from two sources — the lower section of the off-idle discharge port AND the fuel discharging from the idle mixture needle hole. You may only be getting fuel from the idle mixture needle hole when it is wide open, and perhaps nothing from the off-idle discharge port.
Text.jpg
Good luck with your search and quest for enough idle fuel to feed your 3 starving cylinders! :drool: :zzzz: :drinking:
Brad Bodie
Lake Chatuge, North Carolina
Image 1966 Corvair Corsa Convertible

65corvairbuggy
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Re: I want to crush this Carburetor!!

Post by 65corvairbuggy »

Thanks for the info. And glad to know there is some people in my area. That was one of the things I checked since I did have the throttle plates out. And they were correct. Im assuming that it has came down to being a partial internal blockage. Just wish I could figure out exactly where.

joelsplace
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Re: I want to crush this Carburetor!!

Post by joelsplace »

Did you take out the plugs to clean the passages?
114 Corvairs, 5 Ultravans and counting
Northlake, TX

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flat6_musik
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Re: I want to crush this Carburetor!!

Post by flat6_musik »

Just be glad that you don't have a Carter YH!

66vairguy
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Re: I want to crush this Carburetor!!

Post by 66vairguy »

Bob Helt's book on Rochester carburetors is worth the purchase to explain all the different carburetor changes by year.

The 1966 carburetor idle mixture circuit was changed to add an extra port to produce an idle fuel emulsion mix to lower idle emissions while improving idle smoothness. Worked fine, but over the years some carburetors become corroded and that ruins the internal passages. In 67, 68, 69 more things were changed like changing to a fixed idle mixture.

I've had to toss a couple 1966 model year carburetors because they would not idle no matter how carefully they were cleaned. Not saying that is your issue. Bottom line ----- the 1965 carburetors are the least finicky and have all the good features like a power valve circuit and the hot start air port at the base with the rubber and stainless arm.

Make sure your center cluster is fine and not blocked. They had a number of control ports, one is brass that can fall out. They can be warped by over tightening the retainer screws.

The "SMOG" carburetors do work fine - until they don't and usually they are not easily repaired. You can pull the plugs welch plugs to clean the passages, but if they are corroded there isn't a practical way to fix that.

65corvairbuggy
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Re: I want to crush this Carburetor!!

Post by 65corvairbuggy »

What plugs am I taking out to clean the passages?

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bbodie52
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Re: I want to crush this Carburetor!!

Post by bbodie52 »

The process of manufacturing the carburetor body includes some drilling and closing external openings with carburetor body plugs. At least one brave soul recommends drilling those plugs out to allow a more-thorough cleaning, as quoted below...

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:link: http://corvaircenter.com/phorum/read.ph ... 325,844325

How to clean a carburetor quickly.
vaporloc wrote:Date: January 28, 2016 06:10PM

I have also found out the factory put plugs into passageways. Drill them out. Use your Gumout carb cleaner to spray into them. Blow them out with your air compressor. ( one of those thingies you blow up a basket or footballs with work best for that ) You can go to Walmart and buy those split lead fishing sinkers to gently hammer back into the plugs you drilled out. Get the assortment pack with different sizes. You will find one size that hammers in "GENTLY" to act as a plug.

I think the key to using drain cleaner is to pay attention to what the pot metal the carburetors were made of is doing. Have a bucket of water handy to dunk it into. Blow off with air and study on it. Maybe soak for a minute longer and repeat.
:dontknow: :wrench: :confused:

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5 Best Throttle Body Cleaners to Restore Lost Performance

:link: https://cartreatments.com/best-throttle-body-cleaner/
Brad Bodie
Lake Chatuge, North Carolina
Image 1966 Corvair Corsa Convertible

nirvairna
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Re: I want to crush this Carburetor!!

Post by nirvairna »

There are aluminum plugs in the carb base that are there to seal off the drilled idle passageways after drilling. I can't find a diagram of the idle passageway but it is quite long. You might be able to figure it out if you study the base of the carb and where the aluminum plugs are. Removing the plugs can ruin them so you need to have some replacements on hand. You might find the info here helpful http://corvaircenter.com/phorum/read.php?1,1030156

Can you blow carb cleaner from the venturi cluster to the idle adjustment port? If not, there is probably a clog there. If you don't want to remove the plugs you can try some "krud kutter" to clean out the passageway.

HTH

66vairguy
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Re: I want to crush this Carburetor!!

Post by 66vairguy »

The plugs are called "Welsh" plugs. A lot of different sizes. I had a "bad" 66 carburetor a fellow said he could fix it by pulling out all the Welsh plugs and cleaning the passages. It DID NOT WORK. The issue was the idle mixture passages were corroded enough to make the surface rough inside. On 66 -69 carburetors the idle circuit had an extra port and won't work if the idle mixture passages are not smooth.

AFAIK only the idle circuit is affected by the passages. The main circuit well feeds the main run cluster so that is easy to clean. The cluster needs to be clean, but a bright light enables the cluster to be checked for blockages. Sometimes the brass air bleed falls out of the cluster.

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