The other weekend our Yamaha 60 HP on our jon boat alarmed. I ensured water was coming out of the pee hole from back of motor, and the oil/gas mixture was good at 50:1. We let the motor sit for about 5 mins. and cranked the motor and no noise.....it did it again so we made it the landing and came home. The gas line is not crimped , and no prior work on boat was done. Crank battery was charged 2 weeks ago. This is the 1st. time this has happened.......what to do/check please. Thanks in advance.