p5861...Yes, Doc has it right. When cold, pull choke out and after starting, push the choke in as the engine warms up, but just so it still keeps the engine running.
With a manual choke, depending on the outside temp, you may need to start the engine with full choke, or maybe just half choke.
With an automatic choke, a thermostat spring opens the choke as needed according to the engine temp. You just push the throttle to reset the auto choke when starting. As you drive, the thermostat spring adjusts the choke as necessary.
In other words, try to run the engine as little as possible without using the choke, or using less choke the warmer your truck gets. If you push in the choke until the engine starts to faulter, give it a little more choke.
If you have to start keeping the choke out to keep the engine running (when engine is at operating temp), you may be over choking and have fouled the plugs again. Sonner or later if too much choke is used, your plugs will foul enough that they will cease igniting the fuel.
Choking just draws more fuel into the engine. When the engine is cold (especially in winter) it is easier to ignite the fuel with the spark from the plugs when there is more fuel in the cylinder. As the engine warms up, it needs less fuel for the spark to ignite it.
Rub your finger on the inside of the tailpipe. Is it wet black? that is too rich. Is it black/grey but not wet? that is probably OK. Is it more white/grey? then it is too lean. This way can only be a good indicater after many miles though. If you have just made a change in the carb and/or timing, it is hard to judge this unless you have put some serious miles again.
