Are yams and sweet potatoes the same?
1869, in which jerry has a sense of "bad, defective," probably a pejorative use of the male nickname Jerry (a popular form of Jeremy; cf. Jerry-sneak, mid-19c., "sneaking fellow, a hen-pecked husband" [OED]). Or from or influenced by nautical slang jury "temporary," which came to be used of all sorts of makeshift and inferior objects (see jury (adj.)).