Got FSM - What is this

[tpike]

I took everybody's advice and got the emissions FSM. It has been a great help. Found a number of hose routing mistakes by some PO. I still have some resolving since I have a few connections now to sort out. I can't seem to find a references to the actuator on the front of the carb. What is it and what drives it?
Picture attached. It was hooked up to the top of the EGR. And the Modulator was hooked up to a port on the top of the carb!

Thanks in advance
Tom

 

[Landpimp]

that is for the AC idle up. a hose should go from there to a VSV on the right fender, mounted on the headlight washer bottle(if no HW, then someplace on fender)

 

[Landpimp]

Oh and BTW, you need to order some new vac hose.......I have not seen any that look as bad as those on your carb

 

[tpike]

Thanks Landpimp. Previous owner removed the AC so he probably got confused. I agree with the hose replacement. I've been doing some of that as I go. AC idle up. This may explain the high idle I'm seeing. Does anybody know if increased vacuum reduces idle or increases it. I guess I can test that easy enough when I get home. Much thanks. Nice LC lineup!

 

[Landpimp]

if the AC is gone, then just leave it unhooked. Vac will raise the RPM's. But check the screw on the front of the carb(where the rod from the unhooked diaprahm goes to) loosen it up to see if it drops your idle, I don't think it will

Thanks Landpimp. Previous owner removed the AC so he probably got confused. I agree with the hose replacement. I've been doing some of that as I go. AC idle up. This may explain the high idle I'm seeing. Does anybody know if increased vacuum reduces idle or increases it. I guess I can test that easy enough when I get home. Much thanks. Nice LC lineup!

 

[tpike]

Your right it didn't fix it. I am tempted to get the idle down before going through all the emission control stuff but I better do that first. Thanks.

 

[tpike]

Ok. I went through all the emission routing. I didn't look at the fuel cutoff. I also haven't tested all the devices. The previous owner had the choke opener hooked up to the EGR modulator and had two of the altitude lines swapped. The air injection ports have been removed but the pump and hoses are still in place but not plugged (just cut through the big supply hose).
Before fixing the routing the idle was looping between 700 and 1800 with the manifold vacuum oscilatting similarly. Now the engine idles at 2000 (800 with the choke out! - makes me think it is running really lean). Manifold vacuum at 2000 rpm is rock solid at 18 Hgmm. Compression is quite high at 170 psi (engine has been bored out and rebuilt). The idle adjustment screw (hidden pain in the butt #$%#!) doesn't do much. Haven't touched the mixture screw but that is probably next thing to mess with (it doesn't have the plastic lock cover on it). Throttle linkage seems to move pretty smoothly but I think I should try disconnecting it just to be sure it is free enough. I've tried soaking the entire carb (around gaskets and hoses) in carb cleaner with it running and it doesn't seem to make a bit of difference. I should probably start testing the emissions components themselves but I have limited time and I would like to get the idle down a bit so it isn't so irritating for my neighbours. Was wondering if there were any suggestions. I should probably get a timing light and check the timinig. Thanks Tom