question about clutch set-up

[birdkillerz]

I bought a used cart that was in need of finishing or better yet re-finishing. So far so good. I've got one main problem I can't figure for sure on my own. I'm putting a 5 HP motor on it. The former owner was setting it up for a 500 cc snow-mobile engine. He's got this thing that I am assuming is some sort of clutch that turns a short shaft which in turn has a chain going to the drive wheel. My stupid question is, does this eliminate the need for a clutch on the engine shaft? It looks to me that as the engine spins faster this thing closes tighter, it forces the belt to tighten. Thanks.

 

[Kenny_McCormic]

Thats the driven pulley for a sled trans, the clutch is in the drive pulley on a sled.