Serial monitor showing wierd characters only when I add a string to Serial.print

Projects Programming
1

Hi!

This is the snippet in question:

byte buildYValue(int yV) {
  Serial.println("Y: " + yV);
  if (yV <= 1000 & yV >= -1000) { //This creates a cushion for the stop value so the car is not constantly moving
    return 125; //this is the stop value
  }
  else if (yV > 1000) { //if positive value then car is being directed right
    yV = yV - 1000;
    if (yV > 11000) {
      yV = 11000;  //ceiling value for right speed
    }
    return scaleSpeed(yV, 11000);
  }
  else { //Negative x value is to tell the car to go backwards
    yV = yV * -1;
    yV = yV - 1000;
    if (yV > 11000) {
      yV = 11000;  //ceiling value for left speed
    }
    return (scaleSpeed(yV, 11000) + 125); //scale speed to send, add 125 since this is left
  }

}

At the serial.print() part, when I remove "Y: ", the serial monitor shows the values just fine, but as soon as I add that string it starts bugging out.

Things to note:
The values are constantly being sent over a nRF24L01+
I've tried changing the baud rates to both 9600 and 2000000 - no effect

2 
  Serial.println("Y: " + yV);

You cannot concatenate a string and an int in a print statement like that. Simply print them separately

3

Like this

Serial.print("Y: ");Serial.println(yV);

-jim lee