I've had good luck the last week of September for several years. The weather is still pretty warm and I've found fish two ways.

East of Kellys (3-5 miles, 50 ft depth) look on your sonar for bait balls with walleyes beneath. I troll dipsy's and spoons just above the walleye marks. Closer to Kellys (35-40 fow) you can't see them on the sonar but fish have been right on the bottom. Drift fish with crawler harnesses or troll baits right on the bottom.

Good Luck!