Craig, I've replaced all my cables. They were old with corrosion in side. Yes, they were stiff. I used the Teleflex cable (the red ones) and have been pleased. The movements are slick without binding. As for the throttle not staying put, it is an old story. Nat's suggestion is a good one, but the part will be about $20.00. Actually a simple hose clamp will do. You may have to adjust it a few times, though. Good luck.
Mike Meier