Carb help
Thread Starter
Racer
Joined: Jan 2000
Posts: 472
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From: Warren NJ
Carb help
Novice question here:
I have a q-jet on my 350.
When I rev the throttle by hand, should the back 2 larger flaps over the back larger 2 openings the carb open up to let more air in? (I don't know what these are called) b/c on mine, I don't see them open.
I'm thinking maybe they open up only when the car is moving?
Are these the "secondaries"?
[Modified by DaddyO, 7:48 PM 10/12/2003]
I have a q-jet on my 350.
When I rev the throttle by hand, should the back 2 larger flaps over the back larger 2 openings the carb open up to let more air in? (I don't know what these are called) b/c on mine, I don't see them open.
I'm thinking maybe they open up only when the car is moving?
Are these the "secondaries"?
[Modified by DaddyO, 7:48 PM 10/12/2003]
Tech Contributor
Joined: Aug 1999
Posts: 14,370
Likes: 6,364
From: At my Bar drinking and wrenching in Lafayette Colorado
Re: Carb help (DaddyO)
Daddy -
You can't open the secondary airvalves by "winging" the throttle in neutral - there is inadequate airflow through the engine in a no-load condition to allow the secondaries to open. The airvalves will open when engine load demands it.
You can't open the secondary airvalves by "winging" the throttle in neutral - there is inadequate airflow through the engine in a no-load condition to allow the secondaries to open. The airvalves will open when engine load demands it.
Safety Car
Joined: Jun 2002
Posts: 4,844
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From: Pearland TX
St. Jude Contributor
Re: Carb help (DaddyO)
DaddyO....
Post your restoration pic when you have time. I also have a '71 and by far this is the funnest vette I have owned since I am only upgrading age and not having to take things apart to drive it when I want. Luckily I found some previous owners that took alot of pride in this vette and very few things that make it discouraging.
Post your restoration pic when you have time. I also have a '71 and by far this is the funnest vette I have owned since I am only upgrading age and not having to take things apart to drive it when I want. Luckily I found some previous owners that took alot of pride in this vette and very few things that make it discouraging.
Tech Contributor
Joined: Aug 1999
Posts: 14,370
Likes: 6,364
From: At my Bar drinking and wrenching in Lafayette Colorado
Re: Carb help (DaddyO)
The secondary airvalve will open on demand when you go to Wide Open Throttle (WOT) under load. There are 2 things that can prevent this from happening:
1. Most common: Throttle cable incorrectly adjusted or placed in the wrong hole in the carb throttle lever preventing the carb from going to wide open throttle. Check this by having someone push the pedal to the florr (engine off...) and observing that the primary and secondary throttle shafts are going to the full open position.
2. Incorrectly adjusted choke system keeping the secondary lockout lever engaged after engine warm-up. With the engine warmed up, verify that the lockout lever is not engaged in the pin on the passenger side secondary throttle shaft.
If both these items check out okay, your secondaries will work just fine.
1. Most common: Throttle cable incorrectly adjusted or placed in the wrong hole in the carb throttle lever preventing the carb from going to wide open throttle. Check this by having someone push the pedal to the florr (engine off...) and observing that the primary and secondary throttle shafts are going to the full open position.
2. Incorrectly adjusted choke system keeping the secondary lockout lever engaged after engine warm-up. With the engine warmed up, verify that the lockout lever is not engaged in the pin on the passenger side secondary throttle shaft.
If both these items check out okay, your secondaries will work just fine.
