#1: The Boat Is Sputtering and Losing Power
Your boat feels like it's running out of strength (and you've ruled out the No. 1 breakdown reason - running out of fuel). You most likely have a filter problem or fouled plugs.
Replace the in-line fuel filter - you did bring a spare, didn't you? If not, you can at least remove and clear the filter element of any debris, and drain any accumulated water. Afterward, I/O owners should remember to vent the engine box thoroughly before restarting. If you don't, a clogged filter will seem like a minor issue.
It's possible to buy a bad load of fuel, but it's more likely that the fuel went bad while in your boat. Leaving a tank near empty for long periods of time can cause condensation and water in the gas. For long-term storage, fill the tank, and for periods of more than three months, you might want to consider a fuel stabilizer. If so, make sure to run the boat long enough to get the treated gas into the engine as well.
Older tanks might have debris at the bottom, which can get stirred up as the fuel level drops. The best solution might be increased filtration. Consider adding a larger aftermarket fuel filter. And don't forget the spare elements.
If it isn't the gas, it might be the spark plugs. This is a more common problem on older outboards, but might be worth a quick check on any engine. Carry spares, along with the tools to change them.
Spare filter or filter element and a filter wrench.
We hope this List assisted you in your ability to remain calm in the face of possible "on the water" problems, helping to insure many a successful boating adventure.