Kohler 10430 single lever kitchen faucet over time limits the amount of hot water coming out of the faucet. There seems to be a shift in the faucet inner body core (part no. 1036775) where the hot and cold water passage ways don't line up. This is the second faucet I've had to replace due to this problem.

Blocked inlet.
Supply shutoff not open all the way.
Debris in shutoff valve. This happens in older valves with washers.

After removing the oval button cap on the back of the handle loosen the set screw behind it and pull the handle up. The bonnet is threaded so hold the faucet body with one hand (I used a gel hot pad for a better grip) and turn the bonnet counterclockwise. Be careful not to let the entire faucet body turn or it may loosen the bottom bolt that keeps it pulled down onto the base o-ring. Then remove the nut in the same manner and you can simply pull the valve body straight up. To install just reverse this procedure.

The handle has a allen set screw loosen that until the handle comes off then the bonnet nut will unscrew revealing the bonnet cap and washer the cartridge should be under that most kohler's require a special tool to remove cartridge(turn water to faucet off prior to working on faucet,also note how everything is removed it needs to be replaced in same order especially the cartridge,also you should use plumbers grease to coat all seal when replacing everything).

Turn the water off to your Kohler K-14030 faucet under the sink. Open the the faucet to make sure the water is completely shut off. Remove the small setscrew cover from the backside of the faucet handle. You should be able to remove it by hand. Insert an 1/8-inch hex wrench in through the opening and into the setscrew. Rotate the setscrew counterclockwise three full turns; you do not need to remove it. Lift the handle off the faucet. Unscrew the bonnet nut, or cover, from on top of the cartridge retaining nut; counterclockwise until removed. This nut should be remove by hand as well. Use a large adjustable wrench to unscrew the cartridge-retaining nut counterclockwise until removed. Grasp the cartridge stem with pliers and lift it out of the faucet body. You may need to gently rock it back and forth until the suction from the seal ring releases.

was the base installed under the faucet..is there a single hole in granite...faucets usually come with a long base to cover the holes in sink..or with one round ring for granite installation..which the faucet should be mounted on..

take the unit apart, starting with the handles and check for small rocks or derbis blocking flow.

Fix a kohler faucet
most likely the gasket broke inside the lever, you have to replace it.
shut the water off from the angle stop (valve under the sink) both hot and cold.
use an allen wrench ("L" wrench) to remove the tiny screw around the lever, >>>>before you do that place a rag covering the drain for if you drop it<<<< after that pull the lever out, that will show the inside of the faucet. use an adjustable wrench to remove the actuator from the base. when you get that part out you should be able to see the damage to the gasket. At that point you need a phillips screwdriver to get the gasket out and back in >>>>take the damaged gasket to the hardware store<<<< and get a replacement you may have to change more than one. after you get all the gaskets in place, reinsert the actuator and don't forget to tight it up with the adjustable wrench. center it so it would dispense the same amount of hot and cold water, replace the lever reinsert the tiny screw with the "L" wrench. turn on water from angle valves and test faucet.
that should do it and save you about 300 bucks
if it works for you don't forget to rate me

Remove the air-irater at the end of the faucet where the water comes out. That is where 99% of clog are on faucets. If that does not do it then you need to replace the cartridge.

Good Luck and please rate 4 thumbs up for the free answer.

Try draining the system and apply air pressure (min 30psi) to each faucet. Open other hot water faucets to allow pressure to vent. Next try draining and cleaning the hot water tank.

no its somthing in water filter rust or dirt in line.take apart and drain line. thank you for useing fixya please rate me