I'm guessing that your question is prompted by all the time that Huck and Jim spend naked on the raft together.  You may also be puzzled by the term of endearment, "honey," that Jim uses towards Huck.  What you should remember is that there is a big age difference between Jim and Huck.  Jim watches over Huck, is loyal and protective, and loves him.  Calling him "honey" indicates his affection for Huck, but not in a sexual way.  It's also common to address someone as "honey" in informal situations.

And now for the time on the raft: Twain is commenting on Eden, not on homosexuality. You may remember that "everything is free and easy" on a raft. There's no judgement, no rules, just floating and equal respect. The nudity helps symbolize the equality between Jim and Huck.  You may recall that Adam and Eve were naked before they ate the fruit and recognized their difference from eachother.  Every time Jim and Huck hit land, they get dressed again, indicating that difference once again matters.

Personally, I do not see any evidence for the idea that Huck Finn is gay.  In fact, I do not really see any sexuality of any sort going on in the book.

I suppose that you could argue that Huck is gay simply because he is such good friends with Tom Sawyer and because he spends all that time on the raft alone with Jim.  But that seems like really flimsy "evidence" for saying that someone is gay.

I really do not think that this is a work about sexuality.  I think it is a work about conscience and society and the tensions between the two of them.  Of course, sexuality could be part of a tension between conscience and society, but I really do not think that is going on in this particular novel.