I've decided to take a closer look at my Holley NH. My first question is there a tool out there for removing the spray nozzle or do I need to make one?
My second question is if the spray needle I removed is in really good shape, do I really need to remove the spray nozzle to inspect? My last question is about the throttle plate. I can move the throttle lever and plate up and down about an 1/8 of an inch. Is this normal or do I need to replace this assembly?
The tool for removing the spray nozzle is heat and water. Heat the casting that holds the nozzle to dull red and immediately drop the casting in cold water. You won't hurt it! Turn it out with two fingers. Repeat if necessary.
Rapidly cool red hot cast iron - what could possibly go wrong...
Jack's post was spot on.It works,very well. I usually am not in such a hurry that allowing it to cool normally won't work. Once in awhile,I have to reheat one. The carb pctured should have all the passageways drilled out.I would bet they are full of rust/crud.
Use heat as others have said to remove the spray nozzle. Its up to you but if it were mine I would remove it for peace of mind! As far as the throttle plate is concerned it sounds like its worn. The parts are fairly cheap and aren't hard to replace.
The plate should keep the lever from moving up and down.
Somewhere not far down the line is a thread where I ask about the NH. There is a couple pictures that show where to drill out plugs.
I bead blasted the 1 I am working on and then soaked it in the ultrasonic cleaner several rounds before I took it apart. Everything came out ok.
Just aint got around to finishing it.
Tom heating the neck with a propane torch works well and is the easiest thing to do. There most likely be no reason to get it any where near red hot and what ever you do DO NOT get it that hot and dump it in water or you might be replacing a cracked body. Your tool is a screwdriver that EXACTLY fits the slot and I do mean exactly! Mount the carb upside down in a vice and heat the neck, try unscrewing and if it doesn't move heat it further. Don't leave the screwdriver in the hole when heating the neck. One other thing that actually works if it's really stubborn is to heat the neck then drip a few drops of water into the hole and onto the brass nozzle. It will cause the nozzle to shrink and might break it loose. When the nozzle comes out do not forget to remove the gasket that's left in the hole. It'll be rock hard but it's there.
These are the plugs you drill out to clean the passages. Stan Howe suggests brass-wound guitar string. It's rough enough to dislodge crud and soft enough not to damage the body. You can tap the holes and plug them with 8-32 set screws which can easily be removed for cleaning.
Another suggestion Tom: Instead of drilling first get a can of carb spray. The type with the narrow "soda straw" nozzle. Blow through the passages with it. If you blow into one side and it comes out the other the passage is clear eliminating the need for uncalled for work. Keep it simple.