If you've turned the HSN until it's not letting in fuel, it's WAY too lean.. 2 turns out (on an SH.18) HighSpeedNeedleis probably still too lean.. Now that ya have it broken in, set the needles for performance.. Since we know it's too rich at3 turns out, put them both at 2.5 turns out(reset your idle gap to 1mm) and go from there.. Use a couplefull throttle passes to set the HSN (needle where the fuel enters the carb) and use the "pinch test" to set the LSN (needle where the throttle linkage hooks up) Once ya have them set, you shouldnt have to mess with the LSNagain, just slightly tune the HSN for different weather conditions..

Full Throttle passes- Get theengine warm, find a long straightaway and hold it full throttle for about 4 seconds.. (4 actual seconds is quite a long time, so dont short it) Ya want the engine to reach top RPM's and either start missing or flame out (die).. If it doesnt do this, lean the HSN an 1/8 and do the pass again.. (note: this test could make your motor HOT sokeep an eye on your temps! If it gets over 250* (or spit sizzles on the head, shut it down and let it cool off a few minutes.) But what ya want to do is get it "too" lean, then back up your adjustment (richen) it an 1/8 of a turn, and your HSN should be good.. Also check the temp after ya get it set.. If it gets over 250* or spit sizzles on the head, richen it 1/8 and try again.. Ya want it to run good, but ya also want the motor to last..

Pinch test- after you've got the HSN set, and the car is good and warmed up, pinch the fuel line that enters the carb.. Ya want the engine RPM's to rise slightly and shut off within 4 seconds.. If it takes longer than 4 seconds, or rpm's rise substantially, the LSN is too rich.. If there is no rise in the RPMs at all, before it dies, the LSN is too lean.. Adjust in 1/8 turns, drive the car for a bit to let the change take effect, then do the test again..

After this ya should have it set and not have to mess with it as long as the outside temps or humidity doesnt change much.. If it does, just adjust your HSN to dial it in.. Good Luck!

NOTE:If ya dont want to pull your arm off tryin to start these things, ya need to prewarm the engine with a heat gun or hair dryer.. I use an old hair dryer and hold it on the engine about 10 seconds per side, and 10 straight down into the head) After that it'll start on the first pull most of the time!