Have to pump about 20 times to start when cold, where should choke adjustment be set at on the front of the 200 6 cylinder 1968 mustang carborator?

The chokes on those carburetors never worked even when new. You have to(try to) adjust it cold so that it is closed, then, make sure the heat riser is hooked up, watch it as the engine warms up and see if it opens up. Should just take a couple minutes, it would be easier to hook up a bicycle cable to it and pull it on and off. Also, you should be able to adjust the timing a little so that thing will fire right up, check the timing and make sure the plugs are good and the wires. Hope this helps.

Way late to the party, but maybe this will help the next person. I just worked through similar troubles with my 68 Mustang with straight 6. Here's what I learned. First, the choke is finicky... use some graphite and lube up the moving parts. This will make it much more reliable. Then adjust it so it just closes when cold. Make sure that heat pipe to the manifold is installed and that there is vacuum to the choke (hole that follows one of the two attachments screws back to the carburetor). As the engine warms up, you should see this slowly opening up. Then, look into the following...

1. Timing. Mine was spot on, so I didn't look into this one, but make sure it's right.

2. Spark Plugs. Remove, clean/replace and check the gaps (.035). You can learn a lot about what's going on in your engine by what the spark plugs look like, so do a search for that if you suspect anything. Ideally they'll be brown or light grey. Make sure your wires are in good condition (Shutting off the lights and watching for sparks from the wires where a short is occurring can help). Dielectric grease on the spark plug before reconnecting the wires.

3. Distributor. Check points with gauge, make sure wiring inside distributor is in good shape. Check the vacuum advance (remove hose from carb side, suck on it. If it leaks, replace it).

4. Accelerator pump (especially if linkage here is loose). Proper setting is to screw in adjuster screw till it just contacts the diaphragm, then 3.5 more turns. Mine was perfect with an additional 1/4 turn.

5. Look for major vacuum leaks. If you have the automatic trans, there is a large line running back to the vacuum modulator. The line could leak, or more rarely the modulator could leak. (Suck on this hose and see if it holds vacuum... it should). If this guy is leaking, it could allow trans fluid into the engine leaving white smoke. Also check around the carb with starting fluid. If you spray near a vacuum line and the engine revs, bingo!



Okay, so when you start the car, you should press once fully to the ground. This will engage the choke (if the engine is cold). The car should start right up now. There is a fast idle adjustment, so if the car sounds like it just needs more gas, use that (look in the linkages between the choke and the carb). Then, once the car warms up significantly, assure that the choke has fully opened, or you may want to adjust it once more.



Hopefully after this nice afternoon of tlc, your car will purr. This isn't a comprehensive for sure, but it just might be a good outline to work through till you've killed all the issues.

Good luck!