#41  
Old 11-27-2017, 05:48 PM
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Originally Posted by ta man View Post
"Overall the info is pretty good. The CONSTANT "working the throttle lever' drives me crazy though in the video."

X2..

Tom can I add something? Often I see guys adjusting their idle using the primary blades and not readjusting the pump arm clearance. Any change on front blade position will affect the pump arm clearance..even a small change.
They just have not learned yet that placement of the Primary blades to the transfer slot is one of the major setting on the whole carb.
Idle EZE is a great thing, adjusted secondary blades (for additional idle airflow are second best, holes in the blades are the final option.

Tom V.

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Old 11-27-2017, 05:50 PM
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One of the posts I will make at some point will be how to mod your carb for 'home built" Idle Eze.
Tom V.

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Old 11-27-2017, 06:17 PM
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Originally Posted by Tom Vaught View Post
One of the posts I will make at some point will be how to mod your carb for 'home built" Idle Eze.
Tom V.
Cool!

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  #44  
Old 11-28-2017, 09:00 AM
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A little Bit on "Pump Shooters" (since they were shown in the video - a Tech was changing one on the engine).

I like to remove the Pump Shooter parts off the car engine. (Takes no more that 10 minutes to remove the Holley carb completely from the engine.) I do this because it makes carb changes so much easier (on my back muscles) and fewer scratches on the fenders by helpers.

A Holley Shooter Assy has 4 basic parts:
The "Shooter", the Retaining "Shooter" Bolt, the gasket under the Retaining "Shooter" Bolt, and finally the gasket under the "Shooter" itself.

Now when you build the carb, you can glue the gasket under the "Shooter" to the Holley main body so it does not fall down on the Primary throttle blades when you are trying to install it or you can glue gaskets onto a bunch of Holley Shooters and then do the shooter swap like the Tech did in the video. I have a lot of Holley carbs and order parts for them but they only give you 4 shooter gaskets in a typical kit".
Two gaskets for under the shooter and two gaskets for the shooter retention screws (Double Pumper carb).
So I glue two of them on the carb main body when I have the choke shaft and blade out.

Shooters come in different sizes. .026", .028", .030", .031" etc. You can buy Shooter Kits that give you a whole bunch of them. When I worked for Holley I just bought a Cup Full of Shooters right from Holley of the smallest drilled size and then drilled them out for each application. If I drill one out and it is too much shooter volume too quickly then I put a smaller one in and put the modded shooter in the "square" in the box for the new drilled size. 40 Years later I still have a few small hole shooters left and have done a few carbs (lol) in that 40 years.
My shooters were the basic ones. Not "Shrouded" and not the "Extended Nozzle" type. The "Shrouded" nozzles were used on a lot of the 650 and 800 cfm Spread Bore Carbs. The "Extended Nozzle" were for specific applications but can't give you what they were off the top of my head.
Mostly aftermarket carbs.

The "Shrouded" Nozzle shooters were called "Anti-Pull over" shooters if you want to be correct on the name. Sometimes the air velocity past the shooter was strong enough that the shooter would see a slight vacuum and would pull some of the fuel out of the shooter. Not enough to pull fuel and raise the shooter 'check needle' but pull fuel from above the check needle.
The check needle is raised up off its seat by the pump diaphragm pushing fuel past it when the pump is depressed. I always take an old steel check needle and lightly make a proper seat around the Shooter nozzle hole inside the main body. Drop the old needle in the hole, insert a thin drift punch, set the punch on the steel needle, give it a light tap, and then turn over the carb and let the old steel check needle fall on a carb tray for use the next time. Now the gas above the check needle can't leak back to the fuel bowl.
If you have a metering block with a metered orifice on that circuit on the fuel metering block, it is there for a reason.
They put that orifice on some carbs as a anti-heat (fuel expansion) bleed if the pump diaphragm/housing is in a hot engine compartment next to a hot manifold.

The Extended Nozzle shooters have the capability to blast fuel from the shooter and have it actually hit the carb booster. When that happens the fuel is immediately mixed with the air rushing past the carb booster in the venturi area. Works well with larger carbs that want the pump shot fuel mixed immediately before entering the intake.

So again, you do not need to rap the throttle 50 times to verify the shooter is working.

You do need to check the accelerator pump adjustment every time you change the idle blade position on the carb (as mentioned by ta man).
Primary or Secondary positions.

I will discuss Accelerator Pump Volume and vehicle applications (swapping 50cc pump and 30cc pump on the carb) tomorrow but will mention that when the pump moves, and the fuel shoots from the shooter, a 30 cc pump is based on 10 shooter strokes of the pump in a collection vial. So each "stroke" of a 30cc pump is 3 cc and each stroke of a 50cc pump is 5 cc of gasoline. Mr "Rap the throttle 50 times" just put 75cc or more of fuel thru the engine that was not needed and just wasted it for the Video Show.

Tom V.

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  #45  
Old 11-29-2017, 07:46 AM
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Here is a nice PDF file (No Video just easy to read words from Holley). It was printed in 2007 and was updated in 2014.

I mentioned above about Accelerator Pump Shooters and mentioned a few sizes. "Shooters come in different sizes. .026", .028", .030", .031" etc."
The PDF says that Pump Nozzle Sizes are available from .025" to .052". I was not aware of the .052" pump shooter.
"Please note that whenever a .040" or larger accelerator pump nozzle is installed the “hollow” pump screw should also be used."
I personally put in the Hollow Screw at around a .035" shooter or if I am using a 50cc pump on the Primary side of the carb.
Cliff Ruggles and others saw an improvement in their carb tuning efforts by adding that system.
50cc pump and hardware on Primary side of carb, 30cc pump and hardware on secondary side of pump.

I have actually had a person stand close to me when working on a carb and the person say "Hey Dude, you installed the carb backwards."
The Mod works well with Auto Trans cars and a tighter converters.

The Holley PDF say: When changing the pump nozzle it’s best to jump three sizes. For example, if there is currently an off - line hesitation with 28 (.028”) pump nozzle, try a #31 (.031") pump nozzle. Some of the "Rules of Thumb" work pretty well at times. Cam tuning for the Pumps help too.

Holley sells a little Pump Cam Assortment Kit
https://www.holley.com/products/fuel...ts/parts/20-12

9 parts, but the reason why I mention this link is because the Pump Cams are identified: Lightest to Heaviest (pump shot) (Light means a small pump shot into the carb)

"Accelerator pump shot relative to cam color from lightest to heaviest are as follows: Black, Pink, White, Red, Green, Orange, Blue, Brown, Yellow" You do not typically see that info in most magazine articles but it is there if you read a lot of the Holley Info on the web.
The Pink Cam seems to work well in most applications and as you can see you have a lot more choices AFTER that cam.
(That is a Kit worth buying and keeping in your Holley Tuning Parts kit.)

So we have touched on Accelerator Pump adjustment, Cams for the pumps, Shooter Sizes and types, Hollow Screws, and a few other things.
I have a couple more before we stop today.

We have a Accelerator Pump Check Diaphragm installed in the fuel bowl floor of the carb on newer carbs. It is typically orange.
There are also older Holley carbs that had a ball trapped in a retainer that sealed when the pump was activated, otherwise it was open and let fuel into the pump cavity. The Orange Accelerator Pump Check Diaphragm is a better deal.

Remove the old diaphragm, stick the long rubber tip thru the center hole, pull it thru the hole until the retainer "bump" traps it in place and then carefully cut the excess material off the part so that the cut is close to the "retainer bump".
If you do not do this the float will have very little travel and the bowl will have little fuel in it and a hesitation will occur. CUT THE STEM OFF.

Tom V.

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Last edited by Tom Vaught; 11-29-2017 at 08:02 AM.
  #46  
Old 11-30-2017, 09:30 AM
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Today will talk a bit about the "Idle-Eze Idle Air Control parts. Idle Air By-pass was used for years and years on the Carter AFB Pontiac carbs so Barry Grant did not invent that capability. Other people, like myself, made our own "Air By-pass" systems, (Tri-Power is extremely easy as you can add extra idle air with the end carb throttle blades). But we are talking about the Idle-Eze system that Holley now uses because they own Barry Grant's old Demon company.

This article by Maxchevy.com has great pictures so I will use it for explanation purposes.

http://www.maxchevy.com/printable.ht...20Rough%20Idle

The last paragraph in the article: 'On racing engines, the Race Demon carburetor introduces air at idle via a jet instead of the Idle-Eze.
The jet is supplied either in an un-drilled form or pre-drilled." I have been making 'jets' that fit the center area of Holley Base Plates for years.
You drill thru the air cleaner stud hole down to the cavity inside the main body and now extra air will be on one side of the "control jet" that is installed in the Holley Base Plate. If you do a Blow-thru Carb air cleaner stud mod (hollow stud) then the air comes from that location.
Or you can drill holes in the main body casting and use a solid stud to hold the air cleaner on. This is what Holley does today.
Read the article and it can give you lots of ideas.

Tom V.

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  #47  
Old 11-30-2017, 10:04 AM
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"Anti-Pull over shooters"

Do these shooters interchange with standard and long nozzle shooters?

  #48  
Old 11-30-2017, 10:12 AM
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Yep, direct interchange.
Tom V.

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  #49  
Old 11-30-2017, 10:54 PM
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Back on the Idle-eze type modification.
I found a old picture in my files of a Old School Holley modded for Idle Air By-pass with the air cleaner stud used to close off part of the air by-pass system to the lower center part of the carb.

Basically the way it works you drill a bypass hole at an angle towards the air cleaner stud boss.
Then you drill a deeper hole downward from the air cleaner stud boss into the cavity in the center of the Holley carb.
Now if you need additional air you back off (raise) the long air cleaner stud (threaded rod) slightly and let more air pass thru the drilled by-pass hole into the center chamber and then on to the area under the 4 throttle blades. Simple, works well and most do not even know it is there. Reinstall the air cleaner and see if the idle has changed slightly with the air cleaner installed.

Some old Chebby carbs had a PCV valve connection on the SIDE if the carb (see Pic) You could take that fitting out and put in a fixed jet that would allow additional air same as the air cleaner stud mod but again hard to find one of those old chebby 3310 type carbs.

Tom V.
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  #50  
Old 12-01-2017, 12:39 PM
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Today, I am going to talk a bit about "Holley Carburetor Information". When I worked for Holley we had a book called the "Illustrated Parts & Specs Manual".
Holley Carburetion No 36-51 (Rev 2)
Retain 36-51 (Rev 1) for some discontinued models. 1975

Contents:
Numerical Parts List
Adjustments and Specifications
Service Parts List
T.V. (Typical View) and Carburetor Illustrations.
The Price was 43.00 to have it printed and Holley/ Colt Industries Carburetor Division PO Box 749, Warren, Michigan 48090 was the publisher. The manual was red/orange in color and everyone called it "The Red Book"

It had info on things like
"How to do a 'Dry Float Setting' (Fuel Bowl Inverted)
Automatic Choke Settings
Air Vent Valve Clearance (pre-emissions setting)
Choke Qualifying Dimensions
Float Drop settings
Accelerator Pump Adjustments (even in 1975, Holley said go to WOT, push the diaphragm lever down, and measure the clearance. (To make sure the pump diaphragm was never torn and a gas leak could happen.)
Fuel Pressure settings to the carburetor (and a lot more info).

Holley also came out with Service Guides and one of my bosses (Mike Urich) wrote several Books called HOLLEY CARBURETORS over the years. Can still find those in print.

So then you get into a secton of the book called:
"Variable Specifications and Parts"

The List Numbers start at 388-6AS carb (which was a White 3000 Series 150A Engine Carburetor).
The last List Number in this 1975 book is a List # R-7514-A Carburetor (for a 1975 Mustang 2.3L Engine Auto Trans).

That being said on page 121 of the book we have the FIRST HOLLEY DOUBLE PUMPER CARB LISTED: R-4776AAA A/M 600 CFM W/Dual Diaph Pump It gives the Illustration Page for the carburetor 34-1 It also gives the part numbers for the different carb parts. 34-1 Illustration starts on page 241 and goes to page 243 (with two illustrations
The first Part on the list is the Choke Plate and 205 parts later is the Choke Thermostat lever.

I bring this up because each carb series part (4150) kept that illustration number. So Illustration Part # 101 is "Main Metering Body and Plugs Assy - Primary" and Part # 102 is "Main Metering Body and Plugs Assy - Secondary".

So now we know that the Metering Block Numbers for a 4150 style carb will always be basic Part Number "101 & 102".

So all that being written, FIRST HOLLEY DOUBLE PUMPER CARB LISTED: R-4776AAA A/M 600 CFM W/Dual Diaph Pump will have stamped on the Primary Metering Block #4776 and 5882A and the Secondary Metering Block #4776 and 6502A on the top (right side) of the metering block. So with the book I can identify any Holley Double Pumper carb (even if the choke tower is milled off and the guy is claiming it is a 800 cfm carb (not a 600 cfm carb) by reading the metering block numbers. The Carb Throttle Plate assy will be stamped with 4790A somewhere on the base.

So that is how the basic Holley Parts Identification system works.

Tom V.

ps I have the 1975 Book, the 1982 Book, and the 1989 Book which pretty much covers all of the Good Holley Performance carb part numbers before the HP series carbs. (The 1989 Book has all of the older Dominator Carb Numbers in it).

SO IT REALLY HELPS BE A HOLLEY CARB "EXPERT" WHEN YOU HAVE THE CORRECT INFO IN A DISCUSSION
(and actually worked for the people and know where to get the actual specs).

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  #51  
Old 12-02-2017, 11:33 AM
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I did a little search today and found on EBAY a mint "new" copy of the manual and I also found this link to a free (once you sign up) place where you can read the Holley info on the web.

https://books.digitalbeet.com/optin?...+&zoneid=32314

Tom V.

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Old 12-02-2017, 07:45 PM
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Holley Model 4150 carbs vs Model 4160 Carbs and their Fuel Bowls.

Part 1

People get confused on the differences between a 4150 carb and a 4160 carb (assuming that the 4150 carb means "Double Pumper" and 4160 carb means "Vacuum Secondary" carb).

Holley has built (for many years) BOTH carb types. A 4150 style carb can be a "Double Pumper" carb but also can be an early 3310 780 cfm Vacuum Secondary carb with a Secondary Metering Block.

If the carb has TWO Metering Blocks then it is a 4150 style carb.

If the carb has ONE Metering Block and ONE Metering Plate (on the Secondary Side of the carb) then it is a 4160 style carb.

Part 2
Most 4150 style carbs also came with what people call today "Race Bowls". The correct term is "Cathedral" Bowls (see attached pic below).
But Holley Engineers call the "Race Bowl" a "Center Hung Float" Bowl. That is more correct.
You can also have a "Center Hung Float" Bowl that looks like a fuel bowl with a long nose on it.
That Fuel Bowl is many times called a "Cathedral"/ "Le Mans" Fuel Bowl as they were used on some race cars in the 60s with Holley carbs.

One Way to keep track:
If the float hinges in the center of the bowl it is a "Cathedral" Bowl.
If the Float hinges on the side of the bowl it is called a "Side Hung" Fuel Bowl.

On the older carburetors (be it Cathedral or Side Hung Bowl), the fuel level hole (with the brass screw sealing it up) was lower on the Secondary Fuel Bowl because the carb sat on the intake at a slight angle. Front of carb slightly higher vs the rear of the carb because the manifold mounting surface was slightly different. Most know that the back of the engine is lower vs the front of the engine.
Same deal for the intake manifold. So the fuel level port in the bowl was different too.

Double Pumper Carbs tend to have the Cathedral bowls with both ports close to being the same.
You need to actually look to see which one has the lower hole (and some do). That Fuel Bowl goes on the back of the carb.

Dominator Bowls with Fuel Inlet threads on both sides of the Cathedral Bowl have a fuel fitting on one side and a fuel fitting PLUG on the other side. So you can get messed up on the fuel level setting. The fuel "Sight" Hole is the same.

I personally set the float (With the bowl upside down) so that the Top of the float (now on the bottom) is barely covering a portion of the Float Hanger Screws. Never had an issue with floats and fuel level being off.

Dominator Bowl Fuel Fittings are designed for 3/8" steel fuel lines. Older Fuel Fittings were 5/16" steel fuel lines. Both will interchange in the fuel bowl and on a street car (not a Race Car) the 5/16" fittings work fine. Race Car 3/8" fittings and lines are better.

Historically Accelerator Pumps on the Fuel Bowls were originally 30cc (per 10 strokes).
Double Pumpers years later got a 30cc pump on the front bowl and a 50cc pump on the rear bowl.
Dominators get a 50cc pump on both ends.
Sometimes on a street/Tight Converter car swapping pumps and hardware helps with the 60 ft times.

For many years Fuel Bowls used Brass Floats. They were installed in both Race Bowls and in Side Hung Bowls.
They worked very well and rarely had a leakage issue.

Later a Phenolic Float was sometimes added the the rear bowl vs a brass float. So it can be correct to have both types of Floats.

Finally, If you have a Blow Thru Boosted carb, the extra pressure in the fuel bowl can crush the Brass fuel float. So guys put the Phenolic Float on both ends of the carb and the crushed float issues disappeared.

All that being said, the Phenolic Float floats could have other issues with some of the gasoline/alcohol blends out there,
so Phenolic Floats are not perfect solutions either.

So that wraps up my post for the day. (Sorry the second image today does not want to get any bigger when you try to select it).

Tom V.
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  #53  
Old 12-02-2017, 08:33 PM
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Tom,im told the Lemans bowls have a limit of about 500 HP for fuel flo,is that accurate?Tom

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Old 12-02-2017, 10:22 PM
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Actually the Ford 427 GT-40 Engines on the dyno made closer to 540 HP on the Ford Dynos (according to a co-worker who years ago ran that dyno testing) so your number is real close, in my opinion, Tom.

Tom V.

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Old 12-02-2017, 10:57 PM
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What Sean told me.Tom

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Old 12-02-2017, 11:48 PM
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Quote:
Originally Posted by tom s View Post
What Sean told me.Tom
Your Pal Mr Murphy, is a Smart Guy, and a darn good carb man. Tell him I said hello & Merry Christmas.
That Co-worker was a gentleman named George Wilson, may he Rest in Peace!

Tom V.

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Old 12-02-2017, 11:51 PM
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Will do,taking a few carbs down to him next week.Tom

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Old 12-04-2017, 09:42 AM
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Good Monday Morning.

Before trying to fix a carburetor issue, it is wise to identify the real cause of the problem.
Carburetors act the way they do for a REASON

Holley Carburetors are not simple devices. Their job is to deliver the correct amount of fuel/air mixture for any given position of the throttle blades. Carburetors do get dirty over time and will require cleaning of the air bleeds with carb cleaner. (WEAR GOGGLES).
You also need to inspect the carb for tight Linkage Arms and use the minimum amount of spring pressure to keep the throttle blades shut. Multiple lighter weight springs is a good idea vs one Heavy "return" spring.

Carburetor problems generally fall into three areas: rich mixture, lean mixture, and incorrect Carburetor(s) adjustment.
Diagnosing carburetor problems seems relatively easy and is usually the first engine component blamed.
Check timing FIRST. Check for Vacuum leaks in the hose connections, check for hoses left off, check for bad ignition wires
Run the engine in the dark and if you have a "Light Show" around the spark plug wires, fix those first before moving to the Holley carburetor.

Actual Carburetor Problems

1) A Rich Mixture means the Fuel/Air Ratio is wrong at some part of the Calibration Curve for the Holley carb.
Common symptoms of a rich Fuel/Air mixture are:

Poor fuel economy
Sluggish acceleration
Choke System not required for "Cold Starts" of the engine
Sooty or black spark plugs
Sooty or black Tail Pipes
Strong smell of gasoline when the Engine is idling
Rising/falling Idle (Engine will typically slow from assumed idle rpm and eventually stall)

2) Lean Mixtures means the carburetor is delivering less fuel than required or too much air. (Possible Vacuum Leaks)
Typical symptoms of a lean mixture are:

Backfires as the throttle is closed (primarily during coast-downs). (A Coastdown is when the engine is under no load)
Surging/ missing on acceleration (Lean Back-fires)
White or light gray spark plugs
Engine runs only when the choke is partially closed
White or light gray exhaust pipe tip openings Not as common with today's modern fuels vs 1960s fuels

3) Carburetors not syncronized refers to carburetors that have an incorrect adjustment of the fuel/air ratio and the balance between two or more carburetors is poor.

Poor overall performance
Engine tends to stall easily, have to keep it reved up. Tri-Power Carbs with Blade to Bore settings wrong suffer from this.
(some like myself, do run multiple Holley carbs on engines occasionally)
Poor acceleration
Poor fuel economy
Misfires and/or backfires

Correcting Carburetor Problems

Lean Mixtures: This condition is usually caused by installation of after-market parts not calibrated for the engine parameters:

Poorly designed air filter systems for the Holley Bowl Vent Systems, or replacement carburetors of a different type or size.
Fuel level in the Fuel Bowl is set too low, this will change the calibration in the Emulsion Circuit and insufficient fuel will be drawn through the main jet

If no changes have been made to the engine, and it previously ran fine, a lean mixture can sometimes be caused by a leak at the intake manifold or from a leak at a exhaust gasket.

Rich Mixtures: This condition is typically caused by a dirty air filter, but it could also be caused by a poor selection of a replacement exhaust system (muffler) and/or carburetor system (Dominator carb on stock engine).

If the fuel level is set too high in the fuel Bowl, a rich mixture can result.

Idle Eze Screw. Turning this screw clockwise will reduce the amount of air entering the carburetor, and will, therefore, richen the mixture but now you may not have sufficient airflow to keep the engine running at the assumed idle speed.

Incorrect Carburetor Adjustment: Many times, more experience is required or help from a friend needed. This is rarely caused by poor maintenance. More like 'over maintenance'. The enthusiast loses the 'Tune-up' and does not know how to get it back so he buys a different carb. If he reset the original carb back to factory specs the carb issue would very likely go away.

Tom V.

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  #59  
Old 12-05-2017, 11:31 AM
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Since this is the Street Section, a few questions for everyone:

1) How many people actually run a Choke System on their engines.

2) If the car is only a "summer driver" what is your "Engine Fire-Up" Procedure/Method?

3) Are you running heat to the intake or is it a Air Gap style intake with no heat?

Tom V.

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  #60  
Old 12-05-2017, 06:02 PM
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Sprocket Sprocket is offline
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Join Date: Nov 2006
Location: Fort Worth TX
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I have not run a choke for years. I run a Holley 4150HP that has no choke, and I have not had any problems starting it throughout the year. Previously on some other cars that had manual choke on Edelbrock carbs, I did not bother to use the choke. My cars have warmed up fine and fairly quickly with my right foot choke. All of that being said, I live in Texas and winter does not get as severe as other parts of the country/world. Previously, I used q-jet '70s-style choke and other electric chokes.

I start the engine, run the engine at 1800 or so RPMs for a few seconds, slowly drop down a few hundred RPM or so intervals, and then move out when I feel that the engine is ready to smoothly take off. I have no heat to the intake manifold and just run an Edelbrock RPM with the factory engineered gap between the lifter cover and the intake.

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'70 GP - family owned since 1975
462 Butler ported 87cc Edelbrock D-ports
RPM with Holley 4150HP
CompCams 236/242 hydraulic roller
RARE manifolds 2.5" outlets with full exhaust
TH400 13" Continental "Jim Hand Special"
3.42 12-bolt, 245/45-18 Front, 275/40-18 Rear
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