The cleanout outside my house is just an open 2" pipe. No fitting on it. The water from my kitchen sink all flows outside. How do I fix this?

The water from my kitchen sink all flows outside. If you're saying the discharge from your kitchen sink's flowing out on the ground from a open pipe then you have a code violation, Call a plumber to connect your sink back to the drainage system and at the same time have him install a clean out. Good luck, Tom