Does that cable have a Teflon lining, i.e. like the Lokar? If not, that stainless steel sheath will have that grating sound. If it's a boat cable, they usually are set in one position by the hand lever and generally left there while a car type is modulated depending on the driving conditions.
Now, my question - since you don't show that engine compartment, can you run a rod type throttle? I had originally bought a Lokar cable, but have so much engine set back, would have needed to do an ugly loop so built the rod system using some 1/4" rod ends and some steel rod I threaded. This ends up being super slick. I still have cables, but for the trans kick down and cruise, but they weren't needed to be coiled - like this;