Beeping with ignition turned 1/2 way

2017 SHO 66 hours, beeping when key is turned 1/2 way, cranks right up. Made a long run this morning pretty rough water, checked bolts on the top post to make sure connection to the cranking battery was good, no over heat alarm on the way back to the ramp, oil pressure was 78, temp on the motor was 128, water pressure good. Any thoughts, it would be greatly appreciated.

when a motor is giving off a warning buzzer sound its not a good idea to run it take it an have it checked out heat is not the only thing it beeps for water in fuel low oil an such.

Thanks, I did add 10 gallons of gas this morning, checked oil and it was full. I want to be clear, beeping did not occur before the long run, it began once I left and cranked up, headed back to the ramp immediately. I do have 3/4 of a tank of gas that has been sitting for 7 weeks, gas does have about 3 1/2 oz of Stabill Marine in it, wonder if the new 10 gallons from this morning had water in it? I will take it in.