Replace that impeller. Betting that is your issue. I replace mine at the beginning of every season. Make sure you never dry start your engine. I see people start their boats on trailer before launching to make sure it starts and runs. That will kill the impeller very quickly. I run my boat on the trailer from a rubbermade tub with a connection for the raw water hose. This allows me to check and make sure impeller is working properly. If working properly it will just about rip a finger off. Good luck!