[HO455]

Back on post 590 I covered the installation of my electric choke, but I never posted any follow up information as to the adjustments. Mostly because they were done at 0445 in the morning prior to departing for work so photos weren't possible. (Man sometimes I really hate being addicted to food and shelter!) So I finally took time to get a set of photos to use for this post. I have also gotten a new Think Pad and the camera has way too many variables and so the quality of my photos has dropped. Hopefully I can get a better at them over the long run.
The idea is to get the truck to run with a slightly elevated RPM immediately after it starts (and is on the fast idle cam.) And rising no more than about 300 RPM over the next few minutes.
To do this you have to get the choke plate open the correct amount. If not you then you end up using the fast idle screw to bring the RPM up until the engine stays running and then a minute later the RPM has gone up to something like 1800. And since the choke stove hasn't warmed up enough you can't get the fast idle to kick down. Frustrating since no one like to drop it in gear at that RPM.
One note before I start. Most carburetor rebuild kits have choke adjustment measurements shown in the instructions. They are your base line starting point. I won't cover those here. Due to wear, manufacturing tolerances and your particular engine's combination you will need to fine tune those to get proper choke operation.
Picture one shows what your choke looks like before you get in the truck when it is cold. The blue arrow points to the fast idle cam. It is in the lowest position where is should be when your engine is warmed up. Notice the choke plate is fully open. (Vertical)
When before you start the engine you need to pump the throttle once to "Set" the choke. (In weather below freezing I will pump the throttle a second time to give an extra shot of fuel to ensure a quick start) This causes the choke stove to pull the linkages and causing the choke plate be in the fully closed position. See photo 2. Notice the fast idle cam has moved to the highest position. Any time the fast idle cam is up from the lowest position the normal idle adjustment screw is not touching the throttle shaft and the idle is set with the fast idle screw on the passenger side of the primary throttle shaft. The choke plate must be completely closed at this point. If not then the choke stove needs to be rotated (blue arrows) Loosening the 3 screws that secure it and rotating it will cause its linkage to move up or down. (Green arrow) This in turn will open or close the choke plate. (Orange arrow) This is an initial adjustment that may be changed later.
Once you start the engine the choke pull off will pull in (4th photo blue arrow. Compare to the position in the 5th photo) and that will open the choke plate a small amount (yellow lines) This amount is very important for if it is wrong your engine will not idle at a reasonable RPM. Open to much and the engine runs lean and dies. Closed too much and the engine dies from being too rich. To adjust the choke plate position the linkage from the choke pull off needs to be bent slightly. (Photo 5 bend at blue arrow) 2 small vice grips work well for this. Once the engine runs you can adjust the RPM with the fast idle adjustment screw. As the engine warms up the choke stove moves and changes how high the fast idle cam is held up. So as your driving the cam will be dropping when your not at idle. As it drops it won't hold the throttle shaft open as far. With a well adjusted choke your idle RPM will stay about the same (Slightly higher than when the engine is warm) as you drive until the choke is completely open.

Now all of this is a bit of a dance between the different adjustments to get good cold engine operation. If the choke takes too long to come open then you have to rotate the choke stove to the leaner direction.. This may require you to change the bend in the rod that connects to the choke plate to get the to fully close before starting. Or you may need to have the choke stay closed longer so rotating the stove the otherway will be necessary. I normally make 5 to 10 adjustments to get a choke dialed in. Usually do one adjustment a day when the engine is cold. Then I drive it to see how each change affected the performance of the engine.
Now I'm sure I have missed something as I've never wrote it all down before so if I have misspoke or made an error please respond.