My friend has a SX95 rear engine mower he has owned for many years.When it was brought out of storage this years he has a gas leak at the bowl on the carb. It has a 12.5 hp Kawasaki (i think)engine.The gas leaks from a screw with spring on the side of the bowl.This screw resembles a needle valve but is called a drain on the parts list at JD Parts site.If the screw is tightened the engine get no fuel,if it's tuned out 1 turn the engine will start but it leaks badly.Of course he doesn't have the manuals.Does anyone have any idea why it leaks and what to do to repair?Please keep in mind that the referred to screw is in the side of the carb bowl. Any help would be appreciated.

Haven't worked on that particular model, but the typical Kawasaki engine has a Mikuni carburetor with a drain screw as described. It's purpose is to drain fuel from the bowl prior to removing the carb. or to prepare for storage.
Can't say why it will start only by loosening the screw, but the cure would likely start with removing and cleaning the carb. Possibly the float is stuck or the bowl vent is plugged.
Hope this helps some.

tommyhawk