Locke Well & Pump Company

I have a Stenner 85mhp17 that I can't get any suction from. The system is almost 4 years old. I have replaced the roller tube and the suction line and it still doesn't have any suction. The only time I get a flow rate is when I put the unit in water so there isn't any head pressure and then it trickles out. I am thinking that it could be the roller unit. Any suggestions?

IS THE PUMP TUBE RUNNING IN THE MIDDLE OF THE ROLLER ASSEMBLY ? IF NOT ,THE ROLLER IS BAD AND SHOULD BE REPLACED