Kohler forte single control kitchen, low colder water pressure

William, you or a plumber will have to replace the cartridge and seals to stop the leaks. The parts may have life time warranty, check your manual if you still have it. Check the attached links,instruction and guides, Good luck
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Kohler kitchen faucet repair

Hi! Yes it sounds like the spray diverter needs replacing. Kohler .com will have this part online or you could try a plumbing supply shop.

http://411plumb.com/kohler-forte-faucet-troubleshooting-repair-guide/

First thing to check is if it has a strainer on the spout that has debris. The second thing is if you have a sprayer attachment the diverter valve is a chronic problem with kitchen faucets.

First try the tip ariator. it can plug up. then you have to check the inlet system, which includes shut off valves, hoses to the faucet and the cartridge. It is the cartridge that has the small openings, but shut off valve seat material falls back into the feed channel. I usually remove cartridge, cover with a towel and turn on feed water briefly. Often I get little pieces.

Having the same problem and just found the spec sheet. Going to try to repair today. Hope this helps!
http://www.us.kohler.com/onlinecatalog/pdf/1013943_4.pdf

Could be a blockage in the valves and check any filters any where in line.some sinks in kitchen have a filter under sink and check valve to make sure they are opened all the way.

these faucets have a single handel, and have a cartage that can be taken out and cleaned. Low water pressure is caused by minerals in the water to build up in the cartage and slow down water flow.

Your control handle is off by 180°. Remove the handle and turn the cartridge 1/2 turn.

check valves under sink make shure tey are all the way on but spray them into a bucket if you can to see if they are ok.