There is a pattern in some dialects of English called the Northern subject rule where the terminal -s is frequently added to present-tense verbs, particularly when describing habitual actions. This pattern particularly common in Newfoundland, but it's a non-standard practice and should be avoided by people who do not naturally speak these particular dialects.
Popeye's dialect isn't a precise match for anything in the real world, but it's similar what you'd hear from a working-class, early 20th-century resident of New England. I suspect that the writers who created Popeye were at least unconsciously aware of this Northern subject rule as being used by non-formally-educated sailors from the northern Atlantic coast of North America.
Edited: I'm linking a video I found of a couple of Newfoundland natives deliberately exaggerating their local accent. At about 1:05, you hear one of them saying:
"I likes the gravy; I sweats gravy in the mornings."
Then, at 4:25, he lists a bunch of other common uses, including I wants..., I needs..., I likes..., and I loves you. I'm pretty sure that both Popeye and Olive Oyl (his girlfriend) say "I loves you" to each other in the cartoons.
I know someone from Newfoundland who has mostly adapted to "standard" Canadian English grammar (though he still has quite a strong accent), but occasionally I hear him say something like, "I knows that."