c. 1400, "to rush out suddenly and forcefully" (of blood, water, etc.), probably formed imitatively in English or from Low German, or from or based on Old Norse gusa "to gush, spurt," from PIE *gus-, from root *gheu- "to pour," and thus related to geyser. Metaphoric sense of "speak in an effusive manner" first recorded 1873. Related: Gushed; gushing. The noun is 1680s, from the verb.
<a href="https://www.etymonline.com/word/gusher">Etymology of gusher by etymonline</a>
Harper, D. (n.d.). Etymology of gusher. Online Etymology Dictionary. Retrieved $(datetime), from https://www.etymonline.com/word/gusher