Dave wrote:

From what I see turning 360 Deg. a couple of times either way doesn't affect
my receive signal.

That may be normal. The effect of the trimmer can hard to notice.

Do you feel any resistance at all when you turn the knob, or does it
feel like it's not connected to anything?

The knob is turning a shaft that controls how much the capacitor
plates are meshed. A 180 degree turn of the knob will take you through
the entire tuning range (fully meshed to fully unmeshed). No need to
turn multiple turns. Turn it very slowly, and look for SLIGHT
variations in signal level. Sometimes, it's easier to tune to a
frequency with no signal, and tune the trimmer for maximum background
noise. The trimmer only needs to be adjusted when you change bands.

Art N2AH