C! Will not idle unless choked

[Roy B.]

Re: C! Will not idle unless choked

I don't have that info at hand, but the engine should run even if there off. Did you remove the front cover and watch to see the rods are being pulled down. Also look to see that they move up as you add gas. With the engine not running you should be able using your finger push them down and as you let go they pop up. And check your adjustments that it is correct. Make sure they are not bent, it's best to install them last, after you put the Carb to gather.Also check that you have the Carb pump connected in the right hole of arm having two. Check that the pump bore and pump seal are OK. Just some things I can think of off hand. By the way did you replace the rear jets with the front jets?

[Roy B.]

Re: C! Will not idle unless choked

You said when you accelerate the fuel pump gas is gone. With the engine off you should be able to pump the accelerator rod many times and SEE gas flow in to the Carb ( and if it does the Carb pump is OK) so you are getting to much gas or to little gas.

[Wayne Hagopian]

Re: C! Will not idle unless choked

Roy, The accelerator pump provides a good spray through the full stroke so that part is fine. I know I did not swap the jets because I did not remove them I only sprayed them with carb cleaner and they are clear. The metering rods are straight and I have checked them during acceleration and high speed opperation. They are working fine but when the engine starts to stall they pop up due to vacuum loss. I did correct a small vacuum leak in the choke housing which has allowed the engine to idle a little better but now there is a problem with surging at higher RPM's and spitting back during acceleration. I still wonder if someone has swapped the jets or rods or if there is something not right with the throttle valves. I'll take another look tomorrow.

[Roy B.]

Re: C! Will not idle unless choked

Even if you have the timing correct and the Vacuum Advance seems OK. The VA can be bad. Disconnect the VA and then accelerate the engine. If it's OK then the VA is leaking . You said you had the Carb apart many times. Did you compare the lower section GASKET with the old one? ( base plate & center section) There were many different gaskets for the same looking Carb BUT having different hole alignments for a vacuum passage.The engine vacuum is routed to the metering rods (brass) piston that pulls and holds the rods down and I believe it comes through the lower Carb gasket. There are so many people smarter then me on Carbs that should add to this problem.

[Wayne Hagopian]

Re: C! Will not idle unless choked

The vacuum advance is fine and does not leak. The gaskets line up perfectly with each and every hole. The metering rods move up as the engine RPM's increase. Is there a way to compare the rod diameter and jet sizes with the specifications? I know there is a problem in this carb because I have been able to get the 2 barrel performing well with an adapter. The problem is in the WCFB somewhere. Come on over and help me!

[Mike M.]

Re: C! Will not idle unless choked

Wayne,
The Chevrolet Service Manual that covers the model year will list the original jet sizes for your application in the back of the manual. The earliest manual I have is 1963. I looked at it the other day and for the 250hp, 327 cid engine the WCFB was fitted with .108 primary jets and .69 secondary. I think this info is correct, but it is from recall and that is not what it used to be. I do not remember the size listing for the metering rods. Also, the number stamped on the Carter jets does not correspond with the id of the jet, so you need to measure with a drill bit and micrometer.
And it would be even better if a member with the proper service manual can give you the specific info for your car. If nothing else, I will write down the information I have and send it tomorrow.
Mike