Noticed last trip of the summer out my water pressure gauge was bouncing around a lot. Between 5&14 psi while cruising on plane. I took a video but can’t figure out how to upload. Didn’t seem to be over heating or anything. Boat ran great. I’m suspecting poppet valve? Sport master mid. Water pumps less than a year old. Needle on gauge bounces back and forth pretty violently. Good sTeady 3-5 psi at idle. Any ideas?