The secondary air flap is not a choke. It is an air valve. But if it's open it will cause problems.
the air flap is operated by air rushing in when the secondary throttle plates are opened. Translation, when you have your foot in it.
A spring closes the air flap. Follow the rod the air flap is on to the passanger side of the carb. On the very end of the carb you will see a straight screw slot. This slot adjust a tension spring that closes the air flap. There is an allen head set screw on the bottom of the shaft to hold the adjustment in place. Depending on the carb, you turn the adjustement until the spring is loose, then tighten to just contact, then an exact amount of tigtening and tighten the set screw to hold it in place. It is usually between 3/4 and 1 turn on the adjustment. You cannot see the spring or set screw very easily from the top. This is difficult to reach with the carb on the engine, but can be done.
Adjusting this tension spring a bit at a time will make a difference if the carb bogs when opening the secondaries, or if it opens too slow and slows you down.

what was the final outcome?

Aha, crap. It's the choke over the primaries that's open. NOT the one over the secondaries. There's a plastic wire tie that's keeping the primary throttle flap open. It's tied around the linkage near the thermostat (black round plastic thing?). What will happen if I clip off the wire tie? Was this put on because the thermostat is broken?

Steve

probably ... fix that choke... its not very hard

that is definitely "A" source of your starting probs

|UPDATED|6/18/2004 10:46:22 PM (AZT)|/UPDATED|

Ok. So I'll clip the plastic wire tie and see if the choke throttle plate over the primaries opens up when the engine warms up. If not, then I guess I need a new thermostat? How hard is it to replace the thermostat in the carb, when the carb is mounted on the engine?

Steve

munkmunk said: Ok. So I'll clip the plastic wire tie and see if the choke throttle plate over the primaries opens up when the engine warms up. If not, then I guess I need a new thermostat? How hard is it to replace the thermostat in the carb, when the carb is mounted on the engine? Steve

not hard at all... ive seen some idiot rednecks wire tie it open because they think it helps the performance..

some idiot paper clipped the holley 3310 that was on my 69 when i bought it.. and my truck was paper clipped open when i bought it..

what happens is that spring gets worn out and the choke doesnt open quick enough.. so someone drives it and it feels like its starving for air.. but instead of fixing the choke they just wire it open and then rev the hell out of it every morning to warm it up.

anyway... you probably need to replace the black cylinder.. (it holds the spring) also make sure the power lead is hot.. this is the other reason for failure and subsequent southern engineering.

Ben metioned the wire to the choke. If it's an electric choke it needs to have power, but make sure it's grounded as well. Other wise it will, or should, have a heat tube from the intake manifold. This should get hot when the car is running. It supplies heat to open the choke.

Start by getting the tie off of there, and see what happens. The choke coil is adjustabe. It should shut completely and as soon as the car is started it should open a small amount. Then as it warms up it should open the rest of the way. See what it does, how the car acts, and let us know.

I thought that a LS-5 had a thermo choke coil that bolts to the intake manifold,that connects to the coil lever by a adjustable rod with a galvanized tin cover on it, not the black bakilite choke coil housing thats bolted to the carb?

|UPDATED|6/19/2004 11:09:50 AM (AZT)|/UPDATED|

I talked with him in chat last night and told him to go get an electric.. I told him I thought 75 had an electric..

my wiring diagrams indicated this..

also told him to get a relay and run it off the 20 gauge ignition-on pink wire.. (the relay in case of expansion)

he has a tube heater style choke... the tube was missing hence the wiring open..

I called Kragen's for an electric choke. No go. They don't have one. The intake manifold on my LS5 was swapped out for an Edelbrock and I have headers. So no heater tube or linkage is going to the choke. So the choke coil is adjustable? How do I adjust it? Think I can just run the car without a heater tube to the coil? 454's head up pretty fast and I'm thinking there might be enough head just under the hood to heat up the choke coil.

Steve