Our toilet has been working fine until last evening when it started to sound different when flushed. Clearly the water level is too high in the tank. We have the non-ball type mechanism and I see online where it says to adjust the clip but I don't know how to do that. After some flushes the toilet runs but not after every flush. The water level is too high after each flush. We're ready to call a plumber but trying to avoid it if it's a simple fix.

Where is the water level in relation to the overflow tube? If it is over or at the lip, the "clip" you noted is the small metal "V" shaped clip that adjusts the float level. It is on the wire along the side of the float. Squeeze the clip and slide it down a bit. Newer models have a screw adjustment on the float. If it will not adjust, the whole assembly is easily replaced.

The water level is right at the overflow tube. I don't see a metal clip anywhere. I see a black plastic piece that seems to be equivalent to a schematic labeled "water level adjustment clip" but it doesn't seem to move. I haven't tried to adjust a screw although it looks like there are several so I can try that. I was afraid to try without knowing what I'm doing.

When I try to manually move the float lower, the water overflows through the tube but the water level doesn't re-set.

There should be only one long screw attached to the float. If that screw will not turn and lower the float, turn the water off at the stop valve under the tank and flush the toilet. Then push down on the top of the fill valve. The entire fill valve and float should move down and click. Then adjust the float so that the water turns off when the water level is about 1" below the top of the overflow tube.

It will take a little force to push the fill valve down. If it will not push down, reach in under the float and pull up on the locking ring (usually gray) on the shaft. Push the fill valve down one notch and then lock in place by pushing the locking ring back down into place.

C33596 said,
After some flushes the toilet runs but not after every flush. The water level is too high after each flush.

Just so I am clear here, are you saying that the water level is too high in the toilet TANK, AND that you are also having issues with the toilet flushing completely or properly? Please clarify, OK?

Mark