SB 350 - Need some advice

Very first thing you need to do is to purchase the ORIGINAL GENUINE Chevrolet Service Manual.
1973 Chevy Car Repair Shop Manual Reprint Chevelle, Camaro, Monte Carlo, Nova, Corvette
Over 1,200 pages of how to fix/repair/adjust anything on the car, including setting up the choke and rebuilding the carburetor. Written for Chevrolet Dealer mechanics by Chevrolet Motor Division of General Motors.

Not like one of those fosdick Motors, Haynes or Chilton manuals that basically say "disassemble, re-assemble in reverse".

That's the first thing I do when I acquire any new project, is to buy the ORIGINAL FACTORY SERVICE MANUAL.

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For once I'll agree with TechInspector1... especially since your so far away from a cheap source of parts/materials and experienced techs..

Also with that choke, verify the choke brake is working properly. They can be notorious for having a leaky diaphragm and a source of lost vacuum.


:3dSMILE: (just kidding about the disagreeing with Tech -1, he's been sharing good info for decades! he's just had another birthday so I gotta rib him once in awhile!) :LOL:

Hi again !

Thanks for all the reply !
The car runs like a dream, when it fired up, i enjoy every mile in it ! :3dSMILE: And really, who cares about miles pr. gallon? :LOL:

I have thought about buying a tech book, where i can read about wiring diagrams, fuses, engine parts, engine timing and order and so on.
i had first thought about Hanyes Full size repair manuel, but you say the other one is better? What does the book have? It's about 4 times as big as haynes :p Or do i need them both?

And i know I read the most thing on the internet, but i like have a real book - or two - in my garage :)

Tech's advice is sound, and no, you don't need both. As Tech stated, the Original Factory Service Manual is

Quote:

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Originally Posted by techinspector1

Written for Chevrolet Dealer mechanics by Chevrolet Motor Division of General Motors.

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while the Haynes, Chilton, etc are like a Reader's Digest condensed book - they take the Original Factory Service Manual and pare it down, taking out step-by-step instructions and replacing with "Here's a picture, take it apart, replace the gasket, and then reassemble in reverse order" where the OEM book will give you exploded views of the parts, and point out that you have to take off part A before part B will come off. Buy the big book, and enjoy the instruction it gives.

Arr, i understand now, thanks for the clarification !

Hi again !

I got a small minor question, maybe some basic knowledge, but last time i had something with carburator was on my moped :)

Do you need to pump the gas on all small block (with carburators) or is it only when the choke is in the wrong position?

From what i can read i came to this:
1. pump is to close the choke/butterfly
2. pump is to pump gas in the engine
3+ pump is to pump more gas ( equal to much air/wrong choke position)

Is that right?
And i have order the nice service manual book, looking forward to get it ! :)

Let me now if i need to open a new topic, but i dont want to spam the forum completely:)
Have a nice day :)

First, the first pump of the throttle accomplishes two necessary things - 1) the accelerator pump gives an initial "shot" of raw fuel down the carb throat into the manifold plenum, which starts vaporizing to be sucked into the cylinders to support combustion, and 2) releases the choke linkage to "set" based on the ambient temperature. In cold weather that "set" will be almost totally closed, while on a nice 25C day it may only be 1/2 to 2/3 closed if it's controlled by a bimetal coil. Any pumps following only throw more raw fuel into the manifold.

In my experience each car had it's own "happy spot" for best starting, often based on the age. One was one pump to the floor & release for crank, another was two pumps, then feather the throttle a bit during crank, and one (worn out accelerator pump) was three or four good shots, then pump the fuel again during crank. Putting a "kit" in the carb generally brought them back to the one pump, release and crank. Also, it was different summer to winter, and cold start to hot start, because the fuel vaporizes at much different rates with temperature. You find the "happy spot" and live with it, and also use those facts to assess the need for a carb rebuild.

You can start new threads as you wish, and it's handy if you want to focus on a specific question and go back later to review comments. It's your call.

The accelerator pump adds fuel (enriches the fuel charge) when accelerating, without it, the fuel to air ratio would lean out causing a loss of power, poor performance, stalling - etc. etc. etc....

"pumping" the pedal before the first start of the day or when cold, adds fuel to help support easier starting when cold..

Edit, will post later

Thanks for the clarification both of you ! Thats helped a'lot !

I do still seemed to have some morning cold start problems, i have tried everything, 2,3,4, 5 even 6 pump before crank, but can't seemed to get it going ( I have to crank it to more times, before i get a steady idle.

At work, when the car have set for 7-8 hour, it just need to pump, and fire right up, and sound fine )

I took the air intake of to take a closer look at the carburator. Can anyone tell me which one it is
http://s11.postimg.org/qpb0kcrr7/201...17_13_06_1.jpg
http://s11.postimg.org/and2rphfn/201...8_17_13_02.jpg
http://s28.postimg.org/swn183xod/201...8_17_12_44.jpg
http://s11.postimg.org/71bust0g3/201...8_17_12_47.jpg
http://s10.postimg.org/h10nacvrt/201...8_17_12_24.jpg

I think the little thing with the 1 wire must be the choker
To my to my fears only one of the 2 wires was connected !
http://s11.postimg.org/yxcy5cjnn/201...8_17_15_23.jpg
http://s24.postimg.org/4m7fqgbf9/201...8_17_15_33.jpg
Shouldn't it be hook up to something ?
I'm still waiting for my Shop manual, it should come within a few week if it's go straight to the customs.

Does any of you guys think the wire is odd or does it look fine

Have a nice weekend )

Looks like an old, dirty Rochester Quadrajet to me. It has a thermostatic choke, not electric. In your second picture above http://s11.postimg.org/and2rphfn/201...8_17_13_02.jpg, the choke linkage is the vertical bar that drops down into the little heat collector shield atop the intake runner. As the engine warms the heat conducts through the intake, warms the element and moves the choke plate.

Your first start in the morning problem is likely due to the fuel in your float bowls draining down over night, so there's nothing for the accelerator pump to pump until you've cranked enough to re-fill the carb. I think that your first order of business is to either get a carb kit and rebuild the old Quadrajet, or invest in a rebuilt unit from the likes of Summit Racing - http://www.summitracing.com/search/p...%20Carburetors I'm not familiar with their term "Divorced Choke", but that may well be what you have stock.

My Vega is a stubborn start. ( original carb is getting rebuilt now )
My solution is to crank it for three seconds, without touching the gas. Then three pumps of the gas, and it fires right up.

As already said, every carb needing rebuild has its own sweet spot.

That is a Rochester Quadrajet carburetor. They work very well when cleaned and rebuilt. As Roger says, the pumping you need before starting is due to the fuel draining while the car sits for a while. I had the exact same problem with the Quadrajet on my '68 GTO.

If you decide to tackle it yourself - http://www.crankshaftcoalition.com/w...4MV_carburetor

Yep.. rockruster quadrabahg... the wire you show should go to the solenoid. which should extend that "bolt/screw" when the key is turned on... and of course the bolt/screw should retract once the key is turned off. Chevy used these to help prevent "run on" aka dieseling when stopping the motor. You will use the head of the bolt/screw to raise or lower idle speed.


Lot's of guys like the quadrabog.. as you can probably tell, I'm not a fan.