Fuel pump does not suck properly

So servus people, have a problem and that: I got an old part of the Aprilia Mc Gulliver LC from my brother. But now I have a problem with starting the engine. You have to kick for about 5 min until it finally runs and then again 5 min. that you can give gas without it running out. With my scooter is the fuel tank in the floor, so I type that the fuel pump is capput. I hope you can help me and maybe tell me how much new fuel pump ko I don’t know.