HankHill (asker) Mar 1, 2016:

自推式 After noticing this post alone is a top result for 自水, I tried changing the characters and came up with 自推式, which means self-propelled. Thinking the people who originally wrote this messed up the Kanji.

Port City Mar 1, 2016:

Can it be a rotary water gun that comes with a pump? Instead of needing to be supplied with water, it can suck up water. Probably that's what it means.