In "kyuusu", which is actually the romanized Japanese based on the katakana "きゅうす", the last u sound is pronounced very lightly. Alternatively, and more typically, 急須 would be romanized by writing "kyusu" with a line over the first u, indicating a long vowel, which is clearly pronounced, unlike the last u.
You can hear a native speaker reading it on Jim Breen's dictionary site. Just search by the kanji (copy and paste) 急須. Click the arrow to hear it pronounced. The site is here:http://www.csse.monash.edu.au/~jwb/cgi- ... dic.cgi?1C
Note that this loss of notation for long vs short vowels when Japanese words are romanized is common. For example the correct romanization of Tokyo would either be written with a line over the last o or Tokyoo. Thus it is difficult to know how to pronounce these words unless you refer to a Japanese dictionary which will have the correct romanization.
This is probably more than you wanted to know!!