Tri-carb won't idle

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Jun 23, 2009 | 11:22 PM

loflite

Thread Starter

Drifting

Joined: Feb 2001

Posts: 1,539

Likes: 63

From: new ulm mn

Tri-carb won't idle

My '69 shuts off whenever I come to a stop sign. Pumping the gas does not seem to help. After it shuts down, after one or usually two starts, it runs fine as long as I have my foot on the gas. As soon as I come to another stop sign, it'll shut down. The first restart usually results in a very rough run for a couple of seconds and then it shuts down again. It doesn't do this when the motor is cold. It has the factory tri-carbs. What is wrong and how easy to fix? Thanks,

Jun 23, 2009 | 11:28 PM

GDaina

Race Director

Joined: Feb 1999

Posts: 16,978

Likes: 7

From: In Dreams There Is Truth Ohio

could be the inline fuel filters are clogged..remove the fuel lines from the carbs and take out the brass filters...also check the clearance between the pump arm and squirter should be .015. Use a vacuum gauge to set your idle mixture...stop at the highest vacuum on both air and fuel...make sure your choke is working and not binding

Jun 24, 2009 | 11:27 PM

BigBlockTank

Melting Slicks

Joined: Sep 2007

Posts: 2,429

Likes: 0

From: Tucson AZ

Try checking to see if it might be just a bit rich. You said it stars and runs fine when cold? That indicates a rich situation, or stuck choke. Some people can't see the forest for thier eyebrows. Check it out, I'm curious.

BBTank

Jun 24, 2009 | 11:47 PM

loflite

Thread Starter

Drifting

Joined: Feb 2001

Posts: 1,539

Likes: 63

From: new ulm mn

Thanks, I'll check these things out tomorrow.

Jun 25, 2009 | 10:23 AM

1ARACE

Burning Brakes

Joined: Mar 2006

Posts: 915

Likes: 2

From: Lima, OH -- 69 L71 427/435hp

Did you recently change any of the gaskets? Ie. carb or intake gaskets?

If the exhaust crossover on the intake is blocked off it will take a while for the choke to come off.

I'm thinking choke as well...may want to work it a few times and see if theres any binding, maybe spray some white lithium grease on the linkage.

Let it warm up and when it starts to die out check to see if the choke is still closed.

May want to check the temp coil is still good, or the rod didn't come out of it also.

Jul 1, 2009 | 11:40 PM

loflite

Thread Starter

Drifting

Joined: Feb 2001

Posts: 1,539

Likes: 63

From: new ulm mn

Well checked the choke and it is open. Of course, the car idles fine now. It will die out once in a while and you can smell gas, so I think it is rich. Also, after car was parked for about an hour after driving it, noticed gas on the manifold.

Jul 2, 2009 | 10:51 AM

jetjockey

Burning Brakes

Joined: Mar 2006

Posts: 793

Likes: 1

From: Houston Texas

Center carb float level too high?

Jul 2, 2009 | 12:01 PM

7T1vette

Team Owner

Joined: Jan 2006

Posts: 37,637

Likes: 3,113

From: Crossville TN

Disconnect the outer two carbs to rule them out as having any impact on your problem. [Just remove linkage, etc.--make sure the throttle plates for those two are completely closed.] The outer carbs have no ability to adjust idle/choke unless they are partially operating when they should not be.

The instructions for setting choke and carb adjustments is contained in the Chevrolet Chassis Service Manual. Buy/borrow one if you don't have one now. All that info can't easily be communicated via this Forum.