Ok the ones that came in mine were 15 feet long, which I think is part of the problem, It had quite a big loop in the engine well. I think I'll try a bit shorter this time.
Peter, Thanks for the tip I'll try another search. The steering is ok and in pretty good shape, if I changed it I would definitly consider hydraulic. But mainly the throttle cable just had to much friction form either being bent or age coupled with them being too long I believe. So for now I'm just doing the shift cables.
Do yourself a big favor and buy the Mercury Platinum cables. You will forget about the extra dough after you use your boat for the first time...and for many more years. Also, make sure you do not tie up the cables right behind the control box. They need to "wig wag" freely or it will cause a similar condition of stiffness.