I run a restaurant and when it cools off outside and a little breazy it smells like sewage there is a floor drain that I put a solid cover on but that did not help any solutions?

The wax seal under the toilet could be leaking. Cold air is dense and when it is breezy, it backdrafts the vent and air escapes from under the toilet. Try this; take some wet tissue paper and tightly pack it around the toilet base. If the smell stops, you have found the source.

I agree completely with ma0641. Sounds like a bad wax ring under the toilet.

Dose it smell the whole restaurant up or just certain spots like the kitchen or just the dining area or just the bathroom, where?

If the floor drain isn't being used pour a quart of cooking oil down the drain to fill the trap. This will prevent the trap seal from evaporating. If you think the back drafts are the problem consider installing vent caps, (see image. But first replace the wax seals. Good luck, Tom