Most tractor models have the fuse tucked under the bracket of the fuel tank or battery (See figures 1 & 2), to shelter it from exposure to the elements, moisture, dirt and debris. There is a clip attached to the bracket that has red wires leading up to it. Pull the clip down to see the fuse.
On gear shift models the fuse is located on the frame underneath the battery box. (See figures 3 & 4) The battery and battery box must be removed to access the fuse and starter solenoid.
Below are pictures of the fuse location for reference. Your engine may be slightly different.