Hello everyone. I have been fixing up my 1980 Sea King 15 Hp. It had a blown head gasket and bad condenser. I installed a new impeller and sanded/cleaned the pump housing and followed Chrysleroutboarddude’s waterpump video. video. I am concerned about cooling at high speeds. I got it running on both cylinders last week and I noticed that the waterpump works the best at idle and low speeds, but when when on plane, it gives out intermittent flows of water. I don’t have a temperature reader but I pour a bit of water on the head and it starts steaming and hissing even near the spark plugs when I’ve been at high speeds for a couple of minutes. When I go back to idle, the flow is constant and it seems that it is cooling head back down. I just pour water on the head to check the temp. The head of the motor had some dark discoloration when I first got it. This is my first outboard I’ve worked on and used myself so I don’t know much. When I shut off the motor, it seems to start back up fine when I think it is overheating. I attached a video of me at idle and getting up on plane. Since the video I lowered the trim on the motor. Is water hissing on the cylinders head normal at speed? My dad and uncle overheated and broke the motor almost 3 decades ago and I want to avoid doing the same after fixing it up. Thanks ![Smile :) :)](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)