Adjustment needed?
Thread Starter
|
Junior User
Joined: Mar 2003
Posts: 57
Likes: 0
Adjustment needed?
I just finished installing a aluminum intake and a new holley 600 on my 390 in a 76 f150.
runs good except it idels to high. I have adjusted the idel screw all the way out but when I set the timming so the engin runs smooth I can not lower the idel. What is the problem. The idel is around 1200 RPM with the truck in park. I do not think I have any vacuum leaks. I can drive the truck as is but it is not right. The auto choke is working as intended.
Any advise.
runs good except it idels to high. I have adjusted the idel screw all the way out but when I set the timming so the engin runs smooth I can not lower the idel. What is the problem. The idel is around 1200 RPM with the truck in park. I do not think I have any vacuum leaks. I can drive the truck as is but it is not right. The auto choke is working as intended.
Any advise.
Lead Driver
Joined: Jan 2003
Posts: 9,893
Likes: 12
From: Ohio
Sounds like your throttle linkage is NOT letting it come all the way down. Have you tried setting it without the linkage hooked up?
If that is not it then something is definitely WRONG. Re-check all your vacuum ports. Also make sure the choke CAM is not holding the throttle open. There is a small screw that you can adjust how much it holds throttle open. Make sure it is NOT touching with choke off.
There is one other thing that can affect idle, but I can't see it being a problem with a stock set up. There is an adjustment for the secondary throttle blades. It is on the bottom of the carb base on passenger side. If you take carb off, turn it over and look for small set screw. You should not have to do this for your application. Usually it only needs adjusted if you need MORE fuel to get it to idle and be able to use idle mixture screws.
Larry
If that is not it then something is definitely WRONG. Re-check all your vacuum ports. Also make sure the choke CAM is not holding the throttle open. There is a small screw that you can adjust how much it holds throttle open. Make sure it is NOT touching with choke off.
There is one other thing that can affect idle, but I can't see it being a problem with a stock set up. There is an adjustment for the secondary throttle blades. It is on the bottom of the carb base on passenger side. If you take carb off, turn it over and look for small set screw. You should not have to do this for your application. Usually it only needs adjusted if you need MORE fuel to get it to idle and be able to use idle mixture screws.
Larry
