2004 sportster engine smoke ???

[r_bills]

i recently bought an 04 seadoo sportster le 2 stroke. worked great the first 4 - 5 times out, but now i find it revs high, but doesnt go fast. no smoke when i go slow, but when i try to go fast i get white smoke and just rev kinda high. someone suggested to change the spark plugs which i did, and still the same. help please ! any ideas what might be the cause of this? thanks !!