For me the only problem with the puzzle is that the monkey doesn’t look like a wrench and when Guybrush uses it, he uses it like a crank, not a wrench. Other than that, everything is fine. Goofy adventure game puzzles don’t need to fit together like mathematical formulas in order to be “good.”
I think the puzzle would be perfectly fine, if the game somehow told you “hey, you are supposed to use logic to decide which object to focus on, but then you are supposed to try everything on it”. If that were clear, it would be perfectly fine for me.
I mean, making you try everything on the pump is a good way to make sure you are committed to the pump… that you have understood its function. (The same would be to require you to hold the mouse button for one minute on the pump. It would work just as well)
But it needs to be clear that that is the mechanics. that you are expected to do that.
Well, the monkey’s playing is awful. It’s completely out of time. That’s why there’s a metronome, and the monkey is paying attention to it. Tampering with the metronome is logical to me.
I never thought it was “hypnotizing” however, but just “getting the monkey to stop playing” 
yes, tampering with the metronome is logical.
But for this to work , you still need the rule: “Once you have understood the metronome is important, you are supposed to try everything on it”
But I see you talk about “make the monkey stop playing”… I hadn’t thought of that. Hm… Nope. Because then, giving the banana to the monkey would be enough…
Furthermore, this screenshot is quite awkward.
Exactly. As I wrote before:
The monkey is playing the piano and he/she struggles with tempo. It is obvious that you have somehow to mess with the metronome. And if 1) the monkey is using the piano, 2) there’s a nice metronome waiting for your action, and 3) YOU HAPPEN TO FIND A BANANA IN YOUR POCKET… Well, come on guys. I don’t know you all anymore. Maybe playing modern adventures with all those hint systems turned you all in a bunch of softies… 
No, not if the player is a freakin’ monkey. MONKEY=>BANANA. KITCHEN=>CORN
All right, that makes some sense… I admit it.
So the correct reasoning was:
realize by logic that you have to tamper with the metronome;
realize that you don’t have to try everything with the metronome, because the banana is a specially qualified object to try on the metronome, because the banana is related to the monkey.…
I’m note sure if this can be called “logical reasoning” … but it’s true that with this “reasoning” you can solve the puzzle without trying everything on everything.
Whatever you call it, it’s exactly how I solved it.
Yeah, me too.
And I also thought “if a Monkey is perfect for a piano, according to Ron, a banana perfectly suits its metronome, to me”, as a litmus test.
I’ve never thought about it that way. I wouldn’t say he’s playing bad enough to direct the players attention to the metronome and making him want to stop by tampering with the metronome, though. If he would hit the wrong keys all the time, that would be a different thing, I guess.
And the connection to the pump is far fetched nevertheless. The initial issue still is, that it isn’t obvious that you have to turn off the pump in the first place. Well, there is a house blocked by a waterfall, but I would never have thought, that a pump can turn it off. That only makes sense, when you realize that this place might be part of a theme park much later.
It is one of my favourite tunes from the game!
Also hard to play with just the right amount of being out of the beat.
A good job
A better piano, but played every in tempo, and which sucks the soul right out.
The best version still, showing how important the metronome is (and not following it).
Yes, there is. Both the barman and Guybrush make a comment, iirc.
Darn. Why can’t I give more than one like, @Sushi?
I mean, that’s a very explanatory post. I think almost everything has been told about this puzzle, but it is the first time the fact the monkey plays out of beat and that’s a clue is highlighted.
Well he plays in tune, but the tempo is wrong. No metronome can help you hit the right keys, but it’s vital in keeping the right tempo.
@RonGilbert is hanging out here, recently. Maybe he could tell us if the monkey playing out of tempo was an intentional clue for the puzzle.
That’s right, but in this case, you don’t use the metronome to help him, but to prevent him playing at all. If what he plays hurts your ears, you are certainly motivated to do so.
Guybrush: “Jojo’s too into his music to notice.”
Barman: “Hey! Don’t bug the monkey!”
Also it seems you can get Jojo drunk…although I never tried that before.
Barman: “He can’t play piano in that state. Keep him until he’s better.”
Uhm. Are you sure? I remember he said something like that when Jojo was hypnotized
Lol. There’s no need for spoilers here, chaps. The puzzle has been explained ad infinitum in this thread already! 
No, there’s no clue.
It’s OK though because everyone knows the old saying, “you need to hypnotise a monkey with a banana on a metronome before using him as a wrench” 
The problem with this puzzle was the lack of hints and direction. These things would help:
Just these three lines would have given the player enough to make the puzzle seem less bluesky, I think.
My proposals:
