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Re: Rochester Quadrajet (2/12)
 6/7/18 1:00am
73shark
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Overland Park, KS - USA

Vette(s):
1973 Orange Metallic Coupe (orig owner), L82, 4 spd (WR), PS, (A/C & PW (I installed from wrecked 73)), leather, AM/FM Stereo, ran with '65 FI unit earlier & will again some day.


Joined: 7/9/2003
Posts: 554

IIRC, the lockout on mine prevents the secondaries from opening and yes it should release when the choke is fully open.

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1973 L-82 4 spd

Re: Rochester Quadrajet (3/12)
 6/7/18 1:46am
NJAus
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, - Australia

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Currently own a white 1969 427 Big Block Coupe C3 Corvette


Joined: 6/6/2018
Posts: 30

I am not sure that the choke is fully open by looking at the angle? I am thinking that's why it's not disengaging the lockout?
Does the choke coil/rod look like it has been installed backward? Could this be why the choke isn't fully opening?
Re: Rochester Quadrajet (4/12)
 6/7/18 1:32pm
Adams' AppleLifetime Member
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Duncanville, TX - USA

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#1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/ Am-Fm/map light National/Regional/Chapter NCRS "Top Flight" #2-1985 Bright Red/Carmine Cp.L-98/auto Member: NCRS, NCRS Texas, Corvette Legends of Texas


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 First thing...the choke is NOT fully open in that pic. Second thing, what you have circled is the AIR VALVE lock-out. The actual secondary throttle blade lock-out lever is down on the bottom. The design is for the secondary throttle blades to open with the throttle linkage(at 3/4-full throttle), and the air valve is controlled by the amount of air rushing past them with the throttle blades open.....like a variable venturi effect. The air valve assy keeps the engine from bogging down completely when the secondary throttle blades go wide open.
So...first thing I would do is adjust the linkage from the choke coil to the choke lever, and get it to be fully open with the engine warm. Then see if full throttle will open the secondary throttle blades. NOT the air valve( on top), but the throttle blades themselves. If the throttle blades are not opening, the air valve will not move either.
Sometimes, the little lock-out "tang" for the secondary throttle blades will gum up, of otherwise stick, and keep the secondaries from opening. You have to make sure the choke is opening fully when warm before doing anything else. Thumbs Up




|UPDATED|6/7/2018 10:32:16 AM (AZT)|/UPDATED|


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Re: Rochester Quadrajet (5/12)
 6/7/18 6:55pm
73shark
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Overland Park, KS - USA

Vette(s):
1973 Orange Metallic Coupe (orig owner), L82, 4 spd (WR), PS, (A/C & PW (I installed from wrecked 73)), leather, AM/FM Stereo, ran with '65 FI unit earlier & will again some day.


Joined: 7/9/2003
Posts: 554

A good reference source is the Rochester Quadrajet book put out by HP books.

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1973 L-82 4 spd

Re: Rochester Quadrajet (6/12)
 6/7/18 6:56pm
73shark
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Overland Park, KS - USA

Vette(s):
1973 Orange Metallic Coupe (orig owner), L82, 4 spd (WR), PS, (A/C & PW (I installed from wrecked 73)), leather, AM/FM Stereo, ran with '65 FI unit earlier & will again some day.


Joined: 7/9/2003
Posts: 554



|UPDATED|6/7/2018 3:56:20 PM (AZT)|/UPDATED|


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1973 L-82 4 spd

Re: Rochester Quadrajet (7/12)
 6/7/18 8:40pm
NJAus
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, - Australia

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Currently own a white 1969 427 Big Block Coupe C3 Corvette


Joined: 6/6/2018
Posts: 30

Adams' Apple said:
 First thing...the choke is NOT fully open in that pic. Second thing, what you have circled is the AIR VALVE lock-out. The actual secondary throttle blade lock-out lever is down on the bottom. The design is for the secondary throttle blades to open with the throttle linkage(at 3/4-full throttle), and the air valve is controlled by the amount of air rushing past them with the throttle blades open.....like a variable venturi effect. The air valve assy keeps the engine from bogging down completely when the secondary throttle blades go wide open.
So...first thing I would do is adjust the linkage from the choke coil to the choke lever, and get it to be fully open with the engine warm. Then see if full throttle will open the secondary throttle blades. NOT the air valve( on top), but the throttle blades themselves. If the throttle blades are not opening, the air valve will not move either.
Sometimes, the little lock-out "tang" for the secondary throttle blades will gum up, of otherwise stick, and keep the secondaries from opening. You have to make sure the choke is opening fully when warm before doing anything else. Thumbs Up







Thanks I will start with ensuring the choke opens fully.
With the choke coil, I will reverse this as literature is telling me it is around the wrong way.
 
Also the choke coil cover is missing, I know this has an impact and may result in the fast idle not kicking down when warm?

Re: Rochester Quadrajet (8/12)
 6/7/18 9:10pm
73shark
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Overland Park, KS - USA

Vette(s):
1973 Orange Metallic Coupe (orig owner), L82, 4 spd (WR), PS, (A/C & PW (I installed from wrecked 73)), leather, AM/FM Stereo, ran with '65 FI unit earlier & will again some day.


Joined: 7/9/2003
Posts: 554

Without the choke cover on, I don't think the engine heat will warm up the coil as fast thereby slowing the opening of the choke.

|UPDATED|6/7/2018 6:10:51 PM (AZT)|/UPDATED|


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1973 L-82 4 spd

Re: Rochester Quadrajet (9/12)
 6/7/18 9:14pm
NJAus
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, - Australia

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Currently own a white 1969 427 Big Block Coupe C3 Corvette


Joined: 6/6/2018
Posts: 30

73shark said: Without the choke cover on, I don't think the engine heat will ever completely warm up the coil and thereby opening the choke fully.

Makes sense, I don't actually have the cover. As long as the choke closes it is fine, I should be able to just manually kick the fast idle down after a couple of mins?


Re: Rochester Quadrajet (10/12)
 6/7/18 9:42pm
73shark
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Overland Park, KS - USA

Vette(s):
1973 Orange Metallic Coupe (orig owner), L82, 4 spd (WR), PS, (A/C & PW (I installed from wrecked 73)), leather, AM/FM Stereo, ran with '65 FI unit earlier & will again some day.


Joined: 7/9/2003
Posts: 554

Yes you can kick it off of fast idle but if the choke is not completely open, it will not unlock the secondaries.

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1973 L-82 4 spd

Re: Rochester Quadrajet (11/12)
 6/8/18 8:03am
manchestersharkLifetime Member
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Equinunk, PA - USA

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1972 conv, 4-speed, 350, 200hp, numbers match, rally wheels, war bonnett yellow w/white top. good condition, nice driver.


Joined: 10/31/2007
Posts: 1981

Yes, you can purchase a cover for the coil. ALSO, the coil base and connecting rod are in BACKWARDS. The rod should come down straight, and the connection on the front of the coil. That is the way my 72 is set up. It works very well. I have a SBC, BBC may be different. Maybe you have the incorrect coil on there also.

|UPDATED|6/8/2018 5:03:39 AM (AZT)|/UPDATED|
Re: Rochester Quadrajet (12/12)
 6/10/18 5:19pm
NJAus
Former Member

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, - Australia

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Currently own a white 1969 427 Big Block Coupe C3 Corvette


Joined: 6/6/2018
Posts: 30

manchestershark said: Yes, you can purchase a cover for the coil. ALSO, the coil base and connecting rod are in BACKWARDS. The rod should come down straight, and the connection on the front of the coil. That is the way my 72 is set up. It works very well. I have a SBC, BBC may be different. Maybe you have the incorrect coil on there also.



I don't believe the BBC is different, the car has been set up by an inexperienced mechanic here in Australia who claims to have experience in classic cars, all the basics of setting up the carburettor have been missed along with a multitude of other things.