Ether will eventually dry out the cylinder walls, not a big deal on an engine like that with a cast-iron cylinder. It would be better to substitute a shot of gasoline if necessary. What you should do is get into the habit of shutting the fuel off when finished with the generator and allow the carb. to run out of fuel. Honda's also have a drain provision on the carb. bowl so that they can be stored completely dry, which facilitates the next start. If this is one of their newer models that combine the fuel shut-off with the ignition switch, you can turn the switch almost to the "off" position, as that will shut of the fuel before it grounds the ignition.

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'83 300D, 126K miles.