Please be sure to do one thing at a time when tweaking stuff, or you can cause sideffects that will be confusing. . besides, I'm easily confused and it can take days to straighten me out...
It is common for the throttle valve cable (TVC) to fail to return to the full forward position... . it isn't good, but it is common.
You need to tweak the spring or just get a new "universal throttle return spring" to help out.
That spring looks like the one on the throttle lever but it has plain, straight ends so you can 'adjust' it to your needs.
That will help the thing return to the full forward position.
The defuel/shift issue is another thing.
You can use that "adjustment" you mention, on the cable just back of the braket. Pull the TVC fully forward and mark the position of the long slotted part in relation to the actuator rod sticking into the slot.
Hold the thing in place, and use a screwdriver to lift that white colored lever straight up... .
From here you can lengthen or shorten the TVC.
Try moving it back toward the firewall just a touch... try 1/16" first.
Drive it first using the "medium" throttle/RPM say around 1600 RPM's. That will show you your shifts in 'around town traffic. Then do your WOT shifts 1-2-3 and keep an eye on your 3-4 shift FOR LATER adjustment. You don't need to move that cable too far to start affecting the shift point and it's better to work your way up to it than shoot right past the mark you're aiming for and coming back.
Next, your defuel point is roughly around 300 RPM before the pump reaches it's max governed speed. That's a rough average mind you.
So for example, if your pump is set to govern out at say, 3000 RPM.
((On a stock pump the governed speed is usually about 2450 RPM)).
Ok, back to my example... . you can expect to start feeling the truck "fall off" somewere around 2700 RPM. The "pull" will drop away and it will slowly climb that last 2 or 3 hundred RPM till it max's out.
Back the governor screw out about 2 turns and drive it... same as before... keep a close eye on your RPM's and seat of the pants feel for the "falling off" point. If you go too far there is a chance the throttle will not pull it all the way up to the screw. That is not a bad thing and will require some other tweaking. Just watch the throttle stop plate as it moves toward the governor screw (also called the high idle screw)
Ok now the gov. spring. Lets say your pump is currently governed at 3000 RPM MAX!!! When you hit the normal defuel point at around 2700 RPM you'd get the "falling off" feel right...
Well the spring seems to extend that "falling off" point right up to the 3000 RPM mark. In fact you can actually have your RPM "flare" up past that before the governor circuit kicks in and forces the defuel to happen.
Basically the spring will run your pump pretty much "full fueling" up to the governed speed.
Does that help at all???
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