Now for just a moment let's look at some more images regarding the Rochester Power System since that will be the source of many problems for those who continue to use these carburetors. Image one below shows how gas enters the mast. Yellow arrow = through the main metering jet. Red arrow = through the power valve. Image two below shows the mast and setting inside the mast is the idle pick-up tube (normally it will be connected to the air horn securely but many are missing thanks to the fine and careful work of "professional" rebuilders). Image three below shows the idle pick-up tube and to the left of that (retained by my finger) is the power piston. You need to have a good relationship with your power piston. Image four below shows the parts of the power piston. The piston and extending portion and the spring. At this point I'll mention the strength of that spring can be important. It regulates the piston movement. Weaker spring = less vacuum needed to pull it up. Stronger spring = more vacuum needed to pull it up. Many different tension values were used. I don't believe anyone really knows for sure what the answer is and these were all mixed up by "professional rebuilders." Image five below shows the parts of the power valve itself. As you see this is simply a threaded plug holding in place a weak spring and a ball bearing. That is your power valve.
Ok, on to the next part...
~ Jon 1952 1/2 ton with 1959 235 | T5 with 3.07 rear end
