I think trying to be less off-throttle in general would be a good thing. So yeah, we are asking you to hold it down longer and to get deeper under power.
It’s not so much that you need to go faster, it’s that when you lift off, the kart slows. So you’ve got to get those moments when you are off throttle to be specific to turning the kart, basically.
You can’t afford to lift and coast in your quest to be fastest. Obviously you can’t just hold down the accelerator and zoom always, you have to lift and brake.
But the length and timing of that lift should coincide with turn in and the lift will end and be replaced by throttle coming, before or at apex. No coasting!
Please don’t hurl yourself into the wall at the end of the straight. Baby steps on the learning.
Overdriving = trying to make time (reduce lap time) in the entry phase of corners by carrying too much speed into turns.
Your job, as the driver, is to manage the amount of energy/speed in you kart so that you have just the right amount when you get to the apex of turn (the right amount is when the speed/energy that you have at the apex = to the amount of traction force your tires - primarily outside front tire - can provide. If you get this right, the kart can rotate at the correct spot, and with the correct rotational force, so you can get on the gas early & smoothly accelerate out of the turn. If you get this wrong, then:
If you carried too much energy/speed to the apex, then you overload the outside front tire. When that happens, the kart can’t rotate, so you end up understeering wide of the apex. But, the kart MUST rotate to get around the turn, so once you ‘burn off’ the excess speed/energy you carried into the apex, then the kart tends to do a very quick ‘snap’ oversteer, which usually leaves you struggling to control the back end, so you spend time dealing with this instead of accelerating smoothly out of the turn.
If you didn’t carry enough energy/speed into the apex, then you won’t be able to hold the optimum slip angle for the outside front tire all the way to where you want the kart to rotate (your front end will tend to dart towards the apex, or even ‘inside’ of your intended apex… like on top of an apex curb). Also, rotation will often be very lazy because you don’t have the peak energy rebounding off of the outside front tire at the right time to ‘power’ rotation of the kart. If you find yourself at the apex of turns thinking/feeling I could be going faster, so to compensate, you stamp on the throttle, then work on arriving at the apex with enough energy/speed.
“Breathing” the throttle is just another term for a very slight lift off of the throttle. When I said breathing/lifting in turn 2, I meant that it appears (based on the amount of track you do not use at the exit of the turn), that perhaps it is not necessary to lift for the 2nd of the fast double-apex turns (the one that leads onto the front straight).