Thanks. I'm going to Lowes to buy A Korky MaxPerformance 528MP fill valve with the silver cap. I'll get back to you. Stan
Great. Here's a video from Korky on how to install it:
One difference on how you will adjust the refill is that you won't start with a pencil mark based on the previous refill, because your toilet is never fully-refilling. So...
Here's my recommendation: You need to determine the "natural" level of the water in the bowl, the level to which it settles. (A toilet bowl is actually a bit like a regular bowl with a baffle in it; you can only see the part on this side of the baffle, but there is another part of the "bowl" behind the baffle, and when it overflows the water runs down the trapway. When overfilled a smidge, the extra water in the bowl will run over the weir of the trap and down the trapway through the outlet into the drain pipe. In the old days, toilets would always overfill the bowl, and the extra, wasted, water would just flow over the weir as it settled to the natural level.) Get a pitcher or bucket of water, and slowly pour it into the bowl. The bowl will fill up to and beyond its natural level. Let it settle a moment. NOW, mark that spot because that's where you want the fill valve to fill it to.
Cutaway diagram of a toilet. You can see what happens if you overfill the bowl a little. And you can see why it doesn't flush well if underfilled before the start of the flush. It has to fill up, then start the siphon that empties the bowl.