Toto toilet overfilling and overflowing

Have a Toto Caryle 874 toilet. It operated fine for several years, but now the water fill mechanism is causing overfilling of the tank. This causes the excess water to flow over the vertical overflow tube, which causes continuous water running.

It is not the flapper, as it was recently replaced.

The dealer said to remove the white tab on the vertical mounting tube that the blue fill mechanism device is mounted on, then rotate the fill mechanism device counter-clockwise until the water stopped (then replace the tab). This helped for about a week, but now it has started the same problem again. The fill device is now rotated fully against the wall of the tank, so further adjustment is not possible.

Any helpful comments would be appreciated.

Turning it unlocks it to raise and lower it.
This is what adjusts the height...

To repair the fill valve use these instructions

www.terrylove.com/korky

You should only need to adjust the height upon installation. you have a leak in the valve seal. Lowes or a plumbing supply store has a replacement cap (seal) assembly for about $3. Takes about 1-minute to replace once you figure it out. Sometimes you are lucky and it is just some dirt caught in the seal, but it's cheaper and easier to just replace it and be done with it once rather than trying to clean it and finding out you need a new one and having to do it again.

If you search here you can find illustrated instructions, or go to www.korky.com to find the details.

Rg

Folks,

Thank you VERY much.

RG