Holley 4150 adjustment ?'s.
Thread Starter
Melting Slicks
Joined: Oct 2000
Posts: 2,158
Likes: 9
From: N.E. WA
Holley 4150 adjustment ?'s.
This carburetor is a 4779 Holley 4150 750. It has 4 corner idle circuitry and a power valve on the primary and sec. sides.
My first question is: Should the secondary P.V. be the same as the primary?
Second question: How far open do the secondary throttle plates have to be to "enable" the secondary idle circuitry? Can they be open too far?
These will no doubt lead to more questions, but it should get me started. Thanks..
My first question is: Should the secondary P.V. be the same as the primary?
Second question: How far open do the secondary throttle plates have to be to "enable" the secondary idle circuitry? Can they be open too far?
These will no doubt lead to more questions, but it should get me started. Thanks..
Burning Brakes
Joined: Jan 2003
Posts: 755
Likes: 32
From: Roswell Georgia
My first question is: Should the secondary P.V. be the same as the primary?
Second question: How far open do the secondary throttle plates have to be to "enable" the secondary idle circuitry? Can they be open too far?
Hope this info help!
- Greg Smith, Perpetual Corvette Mechanic
Thread Starter
Melting Slicks
Joined: Oct 2000
Posts: 2,158
Likes: 9
From: N.E. WA
Thanks for all the info. My "kit", made by holley, doesn't tell me anything. All the parts are there, but very little info. My secondary plates are open further than my primaries and I was worried that it would mess up the idle transfer. I might have to call Holley cause I can't find my book. I looked at a Holley book in the parts store, but it had nothing of use.
Burning Brakes
Joined: Jan 2003
Posts: 755
Likes: 32
From: Roswell Georgia
I went back and got out an old (1992) rebuild sheet for a Holley 600 with mechanical secondaries. This carb doesn't have a 4 corner idle, but you might be interested in the secondary throttle stop adjustment procedure.
"Back the secondary throttle stop screw out until the secondary throttle plates are closed in the throttle bore. Turn the screw in (clockwise) until it just touches the stop on the lever, then give it an additional 1/4 turn."
This might at least get you in the ballpark. I would definitely contact Holley though to get the correct setting for a 4 corner idle carb.
- Greg Smith, Perpetual Corvette Mechanic
"Back the secondary throttle stop screw out until the secondary throttle plates are closed in the throttle bore. Turn the screw in (clockwise) until it just touches the stop on the lever, then give it an additional 1/4 turn."
This might at least get you in the ballpark. I would definitely contact Holley though to get the correct setting for a 4 corner idle carb.
- Greg Smith, Perpetual Corvette Mechanic
