jayhorowitz,
The 4KY I recently worked on has no oil filter.(2002) Dip Stick is screwed in to check the level. I would check the level while the motor is cold and level. Unscrew it and wipe it off. Screw it back in and unscrew it again to take the reading.(not the handiest) Manual calls for 15W40 oil, though 10W40 should be fine. Run motor briefly and repeat the oil level check if you added oil after leaving it off for a at least 5 minutes to allow oil to drain down.
The choke can be checked while cold by taking the air cleaner element out and looking down to the throat of the carburetor. The butterfly flap of the choke should be closed across the throat of the carburetor when cold. (not run for many hours) You should be able to see this with a flashlight and feel in there with your finger. The linkage on the top of the carburetor to your left connects to the choke and you should be able to "open the choke" by pulling on the rod attached to the lever. When you run the generator the spring in the exhaust pulls this rod to open the choke as it warms up. Should be fully open after ~5 minutes.
Checking the spark plug (do while cold or warm, not hot)Tip should be a tan color, Should not be wet or oily. If oily there is a problem with the engine. (overhaul or replacement) If it is black but dry may be a choke or carburetor problem. If black and wet with gas after running way to much fuel and also a carburetor problem. Exhaust will not be clean.
Observe clean exhaust while running after warm up is normal.
