Golden80

After the cars warmed up I have to rev the motor all the way up to the yellow line before the fast-idle will kick down and return the car to 1000 RPM. What adjustment do I need to make? Is the fast-idle adjustment the round black thingie?

Thanks,
Matt

daily_driver

the fast idle adjustment is a screw next to the choke housing...

lars

Matt -
There are 3 adjustments you can make on the choke:

1. Rotating the black choke cover adjusts the duration of the choke application - how long it stays on. Rotating it clockwise shortens the amount of ti,me that the choke is on. Be sure to fully loosen the 3 screws before you attmpt to turn it.

2. Adjusting the screw at the end of the choke pulloff linkage (up high on the passenger side - just above the choke housing) adjusts how rich or lean the choke runs once the engine starts. This sets how far the choke pulloff will "crack" the choke open upon engine start.

3. The actual fast idle speed is adjusted with the fast idle screw located on the passenger side of the carb, just below the choke housing. The screw head faces forward.

Stop by or give me a call if you need any help or clarification.

adam

lars;

Is the fast idle sticking here on Matt's car? It doesn't seem like it's
too high or something, just stuck.

I get this too - the reason I think it is sticky is that I was trying to
discover why this occurred. I had the air cleaner off and was looking
at the fast idle, when I touched one of the metal pieces there, it
slid down and the engine dropped rpms. In fact, I can put my finger in
there when its stuck and press it down to return the rpms to normal.

Techno

I may be reading this wrong, but I think its operater error and not the fast idle.
You don't hold your foot down you jab the throttle. This really shoudn't be a problem as usually you either need the fast idle or once you drive it the cam drops down a click.
With the engine warm (choke warm) engine off. Open the throttle. on the pass. side of the carb is a little weight with steps on it. rotate the cam or the choke. this sets the fast idle.
Now if you open the throttle the cam should drop. If it doesn't this is your problem something is hanging it up. If it does drop note that it take almost no throttle movement to release it.
One reason for pushing the pedal to the floor is to allow the stepped cam to rotate for setting the fast idle. This only happens if the choke is closing because its cold.

If its an electric choke I think they operate as soon as the key is in the ON position. Do that and watch the choke mechanism while holding the throttle open. Its a little Rube Goldberg machine. Engine doesn't need to be running. takes a few minutes for the heater to relax the choke.

Golden80

I used to be able to jab the throttle very mildly and have it disengage the fast-idle. I've worked on the carb messing with the float and all the internal stuff under the air-horn. I'm sure I've mis-adjusted something. I'll take time to look at it either tomorrow or Friday.

Matt

lars

adam -
Yes, the fast idle cam or cam weight could be sticking a little. It doesn't take much dirt or slime in the rotation point to make it act a little sluggish. However, if the choke is adjusted too far to the "rich" position (the black round cover), the fast idle will stay on too long, and the idle speed will get too high as the engine warms up. By giving the cam weight a gentle "nudge" with your finger, you are pushing the fast idle cam off the fast idle screw, and the rpm is dropping.

You can test the linkage for sticky operation very easily:

Once the engine is fully warmed up and the choke is wide open, simply lift the forward edge of the cam weight (the heavy, steel, silver part of the choke linkage that has the fast idle cam on it) and let it go. It should drop freely and quickly right back down to the bottom stop. Try it a few times and verify that it lifts and drops with no resistance or hesitation. If it works okay, the choke linkage is not sticking. If it does get hung up, it's best to pull the whole choke housing off, disassemble the weight and intermediate choke shaft, and clean things up well.

Golden -
I'm off work on Friday. If you'd like to stop by and check the thing out, I'm just rebuilding Forum members' carbs and distributors in my garage all day, so I can show you how to set the thing up and we can yank it all out and clean it up. We can even do some jetting optimization on your carb if you'd like. I have a fridge full of beer, and you know I don't charge anything for simple driveway tuning - this stuff is just fun. Drop me an e-mail at home if you need my ph# or if you'd like to stop over.
V8FastCars@msn.com