It's a common problem on Bobcat skids sierradmax, fuel pick up line in tank eventually gives up. But you can't use typical rubber fuel hose, installation procedure won't allow it. And don't use typical vinyl tubing, it gets hard really quick when submerged in diesel fuel. I can't remember what the tubing Bobcat uses is called, but it's not vinyl tubing.
Simply get some new tubing from your Bobcat dealer, the strainer/check ball that goes on end of tubing, two hose retainer rings, new seal grommet, and if you presently have a plastic elbow that tubing connects to, replace it with a metal elbow from Bobcat.
Installation goes like this. Slip a retainer ring on end of tubing. Lubricate hose barb on strainer with petroleum jelly, push barb into tubing. Slip new grommet over opposite end of tubing about an inch, slip another retainer ring on end of tubing, lube hose barb on elbow fitting, push barb into tubing. Rub some petrol jelly on tubing between grommet and elbow. Drop strainer into hole in top of tank, slip remaining tubing into tank until seal grommet is at hole in tank. Use a dull screwdriver to push grommet into hole in tank. Once grommet is fitted, push elbow attached to tubing into grommet. Connect your fuel hose and you're good to go.