I have an older toilet (1984) that only seldom does a complete flush with strong vortex. I've read through previous posts and can't find the right solution. It seems to flush perfectly if I put my fist against the opening at the bottom of the bowl (a clean bowl mind you!) and leave it there until the water rises to the rim holes. With liquid-only waste, the water seems to get replaced even without a full vortex flush. The real problem is with certain solid-waste flushes (floating material just won't go down!). Suggestions?