Took my skiff out early in the morning on Monday. Motor cranked fine at the launch and ran perfectly (20 min) to fishing spot. Fished for approximately 3 1/2 hours with motor off and battery turned off. Motor cranked fine and made the run back to the landing. There were a couple of guys throwing castnets and "hanging out" on the dock. I decided to turn the motor off and pack up before trying to fool with them. When I went to start the motor again, it turned over fine, but would not crank. I had to get towed in. The motor has good compression, good spark, good battery. Any ideas on what the issue could be? Any help would be greatly appreciated.