Howdy all got a question for ya. After sitting overnight (kinda cold out too) when I go to start it takes alittle while for the engine to warm up. Basically if I dont give it a little gas for awhile (couple mins) it goes to about 500rpm then coughs and dies. This is the first car Ive had with a carb so Im kinda stupid about it, but it seems like this isnt the way its supposed to be. Any thoughts
Thanx
Glenn

First order of business is to verify proper functioning of your choke. After a night out in the cool air, that butterfly should practically SLAM shut when you press the gas.

You say this is your first carbed car? Well, you have to start 'em a little differently from injected mills. EFI and TBI systems have sensors to handle all of the cold start fuel/air/spark variables. You turn the key and the little computer does all the work for ya.

With a carb, you have to "set" the choke by pressing the accelerator all the way to the floor and then letting it all the way up. Don't touch it again. If your choke is functioning properly, you will only have to turn the key and she should fire right up, hovering in the 1500-1800 RPM range. May climb to two grand, but more than that can hurt your the engine.

Give that motor a couple minutes to warm up, then hit the gas and let off of it (aim for about 2500). This should disengage the choke on a warm engine.

Welcome to the wonderful world of mid-twentieth century automotive technology. For all of our collective gripes about computer modules/sensors/ECM's and all the other shade tree complications, modern fuel systems do allow you to just hop in, turn the key and go - immediately.

The flipside? Go to Taco Bell in minivan and you are absolutely anonymous. Go there in your Vette. Well, you get the picture.

Here endeth the lesson

John

AAhhhhhh ...
Thank you master
Alas my carburater kung-fu is not strong

In time, grasshopper. In time.

"The journey of a thousand miles, begins with a single step."
Confucius 551-479 BC

"hovering in the 1500-1800 RPM range. May climb to two grand"
Well its starts up fine but the hovering thing (I do know about that, I fly on Helo's) aint happening. If my foot aint on the pedal it goes down till it dies
Thanx
Grasshopper

Not to worry.

When the engine is cold, take the breather off completely. As you look at the carb (I'm just gonna assume this is a four barrel) there is a plate at the top of the primary (front barrels). That plate is mounted to a rod that extends outside both side of the carb body. That plate is the choke plate (also known as the "butterfly", Grasshopper). With the choke "off" that plate should be vertical (open) so that you can see down into the carb. Your mission, should you choose to accept it, is to get things set up so that the butterfly is closed (horizontal) when you "set the choke" on a cold motor.

WITH THE ENGINE OFF, pull/push the throttle wide open, then check the choke linkage on the driver's side of the carb. Move that linkage rod up and down. With the throttle open, should move REAL easy and the choke plate should close.

Get some carb and choke cleaner and blast all the crud off the outside of the carb and all linkages (rods). Be careful not to blow all that crap into your carb. Move the linkages as you clean. When everything is loose, try setting the choke.

Let me know what you find and if that solves your problem.

John

Hrm...I'm like the grasshopper larve here...I'll just contiune with my method of holding the foot gently on the gas until the car can shift into gear without dying.

Paragon
Should my hot idle in drive be in the sub 500 range?

Larval grasshopper Paragon:

Negative, Ghostrider.

That warmed up '75 350 should be idling @ 600 in Drive. Double check your cluster tach against a reliable tach/dwell meter if possible.

John

Thank you all. This will be my project for tomorrow. Truly the zen of knowledge runs freely like beer in this hallowed area
Grasshopper

You may find turning the choke coil on the passanger side of the carb counter clockwise just about 1/4 inch may make a big difference in it staying on fast idle long enough. May the force be with you grasshopper. Oops, mixed my shows.
Reaching in from the front passenger side down low you will find the fast idle screw. Looking at the linkage you will see several "steps on the fast idle cam that the screw hits when the choke is closed. With the car warm, set it on the second step and you can adjust the idle to about 1200 to 1600 in park, depending on the specs, and the idle speed will be okay when cold on all steps. The screw on the drivers side is used to adjust the warm idle speed. Drop it in gear and set to 600 RPM. Make sure someone is holding the brake or the wheels are blocked. Once these are right the choke pull off on the right side, a vacuum pot with an adjustment screw, can be tweaked to prevent loading up or lean bog when driving cold. It should open the choke slightly when first started, then the choke coil will gradually open the choke the rest of the way. With a bit of tweaking you can get the car to run smoothly from cold operation to fully warm. Takes a bit of pratice to get it right.
Zen it's okay. (groan)

|UPDATED|4/11/2004 6:37:25 PM (AZT)|/UPDATED|