I was having significant problem with my warm-up lever not providing enough play at the motor end. This meant that when fully up, the lever did not increase the idle much at all. I went through all the link-n-sync steps many times and replaced all other components, including the carb and timing linkages (just in case something was bent or improperly replaced by previous owner. New cables installed as well. Nothing fixed the problem.
What I noticed was that when moving the shifter/throttle back and forth, the throttle cable jacket moved in and out of the control. This meant that the cable was not anchoring tightly in the control unit. A lot of throttle movement was being lost due to the outside of the cable moving.
What I ended up doing was fashioning a shim to fit around the trunion to immobilize it in the control unit. This fixed my problem. This may or may not help you as well.
Also, if you cable is adjusted too tight, you will notice the warm-up lever moving up when shifting back to neutral. Does this happen to yours. If so, the throttle cable is not adjusted perfectly (may partially due to compensate for other problems).
You can check out this link to my post on this subject when I was troubleshooting it. there are many other comments from the experts that may help you as well. It's a long thread so make sure you visit both pages.
http://forums.iboats.com/showthread.php?t=247605
Good luck
