I have a 2001 40hp yahama that seems to rev up all right but seems to surge slightly and seems to be losing power the longer you go. I emptied the gas and mixed a new tank and added seafoam. Took it out for a little spin today for about a mile and couldn't tell any change. I know I probably need to run longer but did not have time. It is pumping water good but seems to be a little warm above the water level. Any help would be appreciated.