First rule of buying anything second hand. FULL service before you start using it.... My own boat spent 3 months going nowhere after I bought it. EVERYTHING got serviced/inspected before I put it in the water!I bought the boat last year, it ran fine and water was coming out the pipe fine. It only happened the once, I’m not sure when the impeller was last changed, I had asked a few companies near me if they’d do it and everyone said no as it’s an old engine….