Craftsman Riding Mower 917.272245 leaks fuel?

Pull fuel line off - if the mower has aged probably just dry rotted fuel lines - common issue on most of these types of riding mowers. I had same problem and replaced the lines, cleaned carb. and installed a fuel line shutoff valve - you might want to get one of those to help isolate the fuel system.

First off, move the mower outside to a well ventilated area. Collection of fuel fumes is extremely dangerous. Now to find the leak. Open your air breather and look down into the "Throat" of the intake and see if there is any fuel in there. If there is then the problem is the shut off valve that is probable attached to the carb and most models has a single colored wire going to it. The only way to fix that is to place a shut off valve in the fuel line between the filter and the carb. If not, then lets move on. Check the fuel filter, is there any sense of a liquid coming from there? The best way to tell is to see if there is a "clean" spot on the chasis or the frame where the motor sits at. If you see the fuel or any of its clean spots on the fuel line between the underside of the seat to the front part of the engine to a small black box. That black box is the fuel pump. There is three lines going to it most likely. One is for the intake, the output and a larger hose that is for the suction on the intake side of the engine. Sometimes there is a fuel leak there as well. Depending on where in the line is going to be the problem. Most of the engines that I have seen that had a small fuel leak has been on the filter side betweek the pump and filter because of the engine vibration.