Problem with servo scanning with Arduino

[SUTO the G]

here is the code:
#include <Servo.h>
Servo scanner;
int scan_angle = 0;  //angle that the scanning servo is at

void setup()
{
scanner.attach(3);
}

void loop()
{

if(scan_angle < 180)  //overflow protection
    {   
      scan_angle += 1;  //turn right
      scanner.write(scan_angle);
      delay(15); 
    }
    else
    {
      scan_angle = 0;
      scanner.write(scan_angle);
      delay(15);
    }     
}
I don`t understand why does my motor make smaller angular turns if I put delay(5). I am trying to make it to scan from 0 to 180 deg and when it reaches 180 to jump back to 0, but I want to make this as fast as possible. If I change the delay(15) to delay(5) it goes faster but it doesn`t seams to go to 180 deg only to 90. Why is this happening? What can I do to make it go to 180 deg fast. Someone please help me!

[jlizotte]

where's the delete key? lol 

[jwatte]

5 milliseconds between pulses may be too small, and the servo doesn't like it when there's not enough pause between each pulse.

If you want it to turn faster, try adding 2 instead of 1 for each iteration through the loop.