Flushing motor in a barrel - any cons?

[Fr. Frank]

But really, the salt residue is going out the pisser hole and will land outside the barrel; and even if a little splashes in the salt will be so diluted by the incoming fresh water that the salt is but a trace, no?

Actually, no. Most of the salt is passed out the motor through the exhaust: both the relief ports and the primary exhaust through the lower-unit hub. Most of the salt is in fact put back into the water you're recirculating.

However, that amount of salt is so small in relation to the 20-30 gallons of water in the barrel/drum, that it becomes insignificant as a corrosive.

It's all good.