In article .com,
says...

In preparation for our lake's 4th of July boat parade, I poured 2
galloons of gas into the boat's gas tank. The boat is a 16' pontoon
with a 9.9 hp fourstroke outboard motor. 1 oz of stabilizer was added
to the gas. The motor started with only a little difficulty. After
warmup and about 1 minute of running, the boat motor suddenly lost
power. I first thought that something (e.g. seaweed, rope) had gotten
caught in the propellers. On the way back to the dock, the engine ran
rough with less than normal power. When I turned off the motor, it
cranked weakly and would not run. Tilting the motor revealed no
obvious problems. The boat was last used 3 weeks ago with no problems.

I would appreciate any thoughts and suggestions. Thanks!

We were said about missing the parade with 27 boats decked out in
patriotic trim. It is one of the highlights of our year. Now I am
worried about the motor.

Seb


Sounds like a 2 cylinder with one dead cylinder. Tried new plugs??
Maybe you fouled a plug, or the plug is just plain shorted.

Thanks for the suggestion about plugs.

I did manage to get it started later in the afternoon. I took it
around the lake. When the engine is running at high or medium speeds,
it seems normal. However, when the engine is running at low speeds
approaching trolling speed, the engine runs rough and eventually dies.

Thanks again,

Sebastian