I am trying to do a rebuild on my Ford NH carb. I'm still in the disassembly stage. I need to remove the brass plugs to clean out the passages. Haven't found a good diagram of where the passages start and end but have an idea from numerous old forum threads. There is one open passage from just left of the choke axle that goes to the float chamber. I assume that is an overflow port (?). There is a brass plug in the flange that attaches the carb to the manifold and I assume that is the air vent that loops past the throttle butterfly. I think there is a port that runs from under the ID plate to an opening inside the housing where the needle valve seat screws in. There is a brass plug to the left of the ID plate that goes - I'm not sure. There is a third brass plug just in the float chamber about 1/2 inch below the float gasket flange edge whose destination is also a bit of a mystery. Those are the three brass plugs that I assume everyone says should be removed to clean and clear the passages. I have a 4th brass plug which is larger and below the above described plug and about a 1/4 turn counter clockwise from the third plug described. What is it and should it be removed also?
I think I have gleaned that the 3 brass plugs should be drilled out with a slightly smaller bit (smaller than 1/8").
Finally, there are instructions to remove the ID plate but don't damage the pins or the plate. Don't use a flat screw driver, but it doesn't say what should be used and how to remove those brass pins.
To summarize: What is my 4th plug? How do I get my ID plate off without damaging it or the pins? Is there a diagram that shows the path of these ports?
Will this thread help?
All three of these plugs are in different parts of the same passage, which carries a little fuel past the throttle plate when it's closed. Gotta go. More later if needed.
This photo shows the 4th plug I have. It is below one of the three plugs that is shown in the photo above and about twice the size of the others. I don't know what it is or if it should be removed and cleaned.
The thread that Dave sent to me suggests that you grind the heads of the pins on the ID plate off and then drill out the old pins and put new ones in.
Doug: I would not remove the tag. The passage it covers is easily cleaned from inside after you remove the spray needle seat. I drilled and tapped the brass plugs for a #4 machine screw and 'pulled' the brass plugs with a stainless steel machine screw. jb