Originally Posted by Chris West
don't worry Nova have stoped putting a middle screw on their engines the adjustment is so delecate that its not needed. anyone who does touch a middle screw should have their fingers chopped off unless they really know what they are doing.
LOL, thats a bit harsh...but funny and gets the point across. I actually have a large lot of brand new motors of the same kind , all the 3rd or middle range needles are set slightly different. I think if anything the people who assemble it just get it flush.
I know I didnt want anything to happen to my 3rd needle adjustments. So I take a hobby knife and etch a line showing me how the carb should be set. Then you can kinda go in and tune that needle without worrying about setting it back to factory. Just dont go turning it to far , you want to keep it at the same flush level , just a little leaner or rich and see how it goes.
Its basically just a little tiny final tweak you can do if you notice its running a bit weird in the mid range. But yeah most people shouldnt mess with it unless you really know what your doing , you will probably not even notice it and its not going to make or break you.