I have a friend with a 05 Yamaha 70 4 stroke. He had parked his boat after a fishing trip and a week later he checked the oil and it was up to the top when he removed the dipstick plug. One mechanic told him to change the oil and run it hard with the motor trimmed down for 45 minutes and check the oil. With gas going in the oil, it would scare me to death to run it that long with the oil getting that thinned out with that much gas in it.
Any suggestions as to the cause and if running it that long without checking the oil is a good idea?