Texas, I am not sure that I understand your suggestion.
The manifold is on the bench.
When I first picked up the manifold from the shop, the shaft seemed to rotate quite easily. Now, the shaft still rotates but there is some resistance in some spots.
Once I got the manifold home, I noticed that there was not much spring pressure at all trying to keep the butterfly in the cold position. At that point I wound the spring one turn tighter figuring that the shop might have undone it and not retightened it.
If I heat the spring with a torch, it relaxes the pressure on the butterfly allowing it to move more freely toward the position that would force the exhaust to go down into the exhaust pipe rather than up under the carburetor, but it doesn't relax it enough for the butterfly to close off the upward flow much at all.
If I manually move the butterfly to either extreme, it gets a bit stuck.
So, at this point I am guessing that what it needs is some sort of lube.
I have attached a couple of photos which I labeled with what position I believe the butterfly should be in when cold and hot. (I am confused as to what we are calling open and closed.)
Nick 1940 KC Model 1/2 Ton Pickup Project (with '37-'39 Bed and what we think is a '42-'46 Frame) Taos, New Mexico
