Changing player speed for crouching

I set the horizontal player speed to 1500 when the scene starts I set the speed to be 70 when the down arrow is pressed and when its released to be reset back to 1500 speed but for some reason the value? is different, now 1500 is slower then when it started

Pay attention to your actions
1st you change maximum speed
Then you change acceleration speed

Maximum is how fast it can move
Acceleration is how fast it will get from 0 to max speed

I always set acceleration to something absurd like 400000
And now i only manipulate max speed