Reel advice?

Hi Guys

I have an old daiwa magforce reel that is in excellent shape that has the following problem:

1. When turning the handle and the little knob, that one uses to set rate at which the spool runs when in free spool mode, is fairly loose, the drag can be at any setting, everything functions as normal.
2. When the knob is adjusted, say to throw a 3 once sinker, and starts to get tight on the spool, its start to get difficult to turn the handle, and the drag has to be set fairly tight, when the drag is loosened the handle turns freely and the spool stops turning?

any suggestions?

If u use bigger sinkers what hapens?

to use a bigger sinker is the problem, the adjustment knob has to be tightened even more to accomodate the bigger sinker and thus the turning of the handle gets even worse.