I guess I didn't word that correctly.

The needles are VERY VERY sensitive to adjustments, but they don't REACT instantly. Make a tiny tiny adjustment and then WAIT for the engine to react. A little 1/16th turn lean on the high speed makes a HUGE difference.

I think this is where some of the guys get into trouble. They whack the needle valve and nothing happens instantly, so they whack it again. Engine quits. "My XXX won't run at high speed. Everytime I adjust the needles, nothing happens and then all of a sudden it just dies"

Gasser needles are EXTREMELY sensitive to adjustments--iin that a little bitty adjustment has a HUGE effect.

BUT--they don't REACT to those adjustments instantly. They take a few seconds to rev up or down when you turn the screws.


I make a tiny adjustment--never more than 1/8th turn at MAX--and then I listen to it and cycle the throttle a few times. Then make another very small adjustment and wait for the effect. Most of my adjustments are the thickness of the slot in the adjustment screw. Sometimes less. I just never notice an instant response from the engine. Mine always seam to take 5 or 10 seconds to respond.

For example:
If I need to lean the high end because I just bought a used engine from a guy at sea level, first thing I'll do is just start it. It' richer than Bill Gates at this point. I'll tach it and then shut it down. Usually only get about 5000RPM out of it with sea level needle settings.

I'll lean the high end 1/4 turn and start it. Tach it. Still rich.

Shut it down and lean the high end another 1/8th turn. Start it. Getting close now. Tach it. Usually, getting up in the 6500RPM range by now.

Put the tach away.

Now I lean it about 1/16th turn at a time and just listen to it. But, my adjustments take a little while to notice the effect. I've leaned a G-62 while it was running WFO (carb rotator block installed) and 1/8 turn adjustment took about 10 seconds for the engine to actually rev up and hold steady. Lean another little bit--thickness of the slot in the screw--takes another 10 seconds to rev up and hold steady.