Holley 600 questions...
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Lead Driver
Joined: Apr 2002
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From: Littleton, New Hampshire
Holley 600 questions...
I think I may know the answer to these questions but I'd like verification.
(1) Electric Choke Adjustment - Some carbs have a fast idle adjustment screw (like a quadrajet) but can't find one on my single inlet Holley 600. I assume the only choke adjustment is rich or lean by turning the cup where the power lead is attached. Is that correct? I keep turning it to the left to close off the choke more but the engine still dies when cold. If it has a fast idle adjustment, where is it?
(2) Vacuum Activated secondaries - I assume if I remove the vacuum hose that goes from the top of the carburetor just under the air cleaner that runs down to the bottom right rear side and plug that inlet that the secondaries will not open. Is that correct? I'm thinking of doing this to as an economy move. Has anyone else done this? Will it save me any gas?
Thanks for you comments.
(1) Electric Choke Adjustment - Some carbs have a fast idle adjustment screw (like a quadrajet) but can't find one on my single inlet Holley 600. I assume the only choke adjustment is rich or lean by turning the cup where the power lead is attached. Is that correct? I keep turning it to the left to close off the choke more but the engine still dies when cold. If it has a fast idle adjustment, where is it?
(2) Vacuum Activated secondaries - I assume if I remove the vacuum hose that goes from the top of the carburetor just under the air cleaner that runs down to the bottom right rear side and plug that inlet that the secondaries will not open. Is that correct? I'm thinking of doing this to as an economy move. Has anyone else done this? Will it save me any gas?
Thanks for you comments.
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Joined: Dec 2001
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From: Louisville,Ky.
1) The fast idle screw is on the linkage under the choke linkage almost facing upside down. It is usually easier to access with the carb off.
2) No, the vacuum line that you speak of draws air thru the choke. You can not remove vacuum from the secondaries. It is drawn thru a hole in the primary side of the carb. You can get a spring kit from Holley and install the black spring. It is very stiff and will keep them closed most of the time, especially on a smaller cubic inch engine.
They probably don't open that much now unless you are really into the throttle hard.
2) No, the vacuum line that you speak of draws air thru the choke. You can not remove vacuum from the secondaries. It is drawn thru a hole in the primary side of the carb. You can get a spring kit from Holley and install the black spring. It is very stiff and will keep them closed most of the time, especially on a smaller cubic inch engine.
They probably don't open that much now unless you are really into the throttle hard.
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Post Fiend
Joined: Dec 2003
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From: "Islander"
If you open the carb and hold it at full throttle with motor off the fast idle screw can be reached with a 1/4" box wrench for adjustment without pulling the carb. Both the choke and fast idle will take a couple cold morning starts and adjustments to get set properly.
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Lead Driver
Joined: Apr 2002
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From: Littleton, New Hampshire
Originally Posted by LxMan1
1) The fast idle screw is on the linkage under the choke linkage almost facing upside down. It is usually easier to access with the carb off.
2) No, the vacuum line that you speak of draws air thru the choke. You can not remove vacuum from the secondaries. It is drawn thru a hole in the primary side of the carb. You can get a spring kit from Holley and install the black spring. It is very stiff and will keep them closed most of the time, especially on a smaller cubic inch engine.
They probably don't open that much now unless you are really into the throttle hard.
2) No, the vacuum line that you speak of draws air thru the choke. You can not remove vacuum from the secondaries. It is drawn thru a hole in the primary side of the carb. You can get a spring kit from Holley and install the black spring. It is very stiff and will keep them closed most of the time, especially on a smaller cubic inch engine.
They probably don't open that much now unless you are really into the throttle hard.
Post Fiend
Joined: Dec 2003
Posts: 6,658
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From: "Islander"
Favorite brand is like a Rambler Studebaker thing.
My choice is a Holley hands down, mileage difference
if any would be slight if none provided both brands were set up
and jetted for your particular motor.
My choice is a Holley hands down, mileage difference
if any would be slight if none provided both brands were set up
and jetted for your particular motor.
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Lead Driver
Joined: Apr 2002
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From: Littleton, New Hampshire
I have used both brands in different vehicles but really have no favorite. Whatever works best at the time is the brand I want but I can't live with 10 MPG so I'm looking to improve mileage any way I can. I'm not a carburetor guy so I'm not familiar with the process of changing jets. The jets in it now are supposed to be "stock" according to the rebuilder...whatever stock is. The engine is basically stock except for an RV cam.
Moderator
Joined: Dec 2001
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From: Louisville,Ky.
The choke draws air internally, the vacuum line hooks up so that the air being drawn into it from the choke is inside the air cleaner so that it is filtered by the air filter.
As far as jet size, I need the list number off of the choke horn to see what it came with. It should be on the front, righthand side.
As far as jet size, I need the list number off of the choke horn to see what it came with. It should be on the front, righthand side.
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Post Fiend
Joined: Dec 2003
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From: "Islander"
After working with Holley 1850's the last 30 years be it used or brand new plus rejetted I find the 670 SA comes up leaner on the cruise without the lean surge problems that 1850's would have if leaned down the same on the F/A ratio gauge. I believe Holley made improvements when they came out with the SA besides a slight mileage improvement.
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Lead Driver
Joined: Apr 2002
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From: Littleton, New Hampshire
Originally Posted by LxMan1
The choke draws air internally, the vacuum line hooks up so that the air being drawn into it from the choke is inside the air cleaner so that it is filtered by the air filter.
As far as jet size, I need the list number off of the choke horn to see what it came with. It should be on the front, righthand side.
As far as jet size, I need the list number off of the choke horn to see what it came with. It should be on the front, righthand side.
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Lead Driver
Joined: Apr 2002
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From: Littleton, New Hampshire
Originally Posted by albung
blown power valves cause terrible gas milage too
Thread Starter
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Lead Driver
Joined: Apr 2002
Posts: 8,813
Likes: 13
From: Littleton, New Hampshire
Originally Posted by LxMan1
The choke draws air internally, the vacuum line hooks up so that the air being drawn into it from the choke is inside the air cleaner so that it is filtered by the air filter.
As far as jet size, I need the list number off of the choke horn to see what it came with. It should be on the front, righthand side.
As far as jet size, I need the list number off of the choke horn to see what it came with. It should be on the front, righthand side.
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Joined: Dec 2001
Posts: 22,436
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From: Louisville,Ky.
80457 is the list number. I have one of these myself. It was on my 351W, then I swapped it to my 460 so if I ever sell the truck, I will have my Edelbrock 750 that I like better on my 351W. It came with 69 jets if there is no -1 or -2 after the 80457. It is has the -1 or -2 then it came with 64 jets.
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Lead Driver
Joined: Apr 2002
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From: Littleton, New Hampshire
Originally Posted by LxMan1
I would try dropping about 2 sizes and see how that works.