I rode 8 miles yesterday with no problems. I came back and parked the pwc on some carpeted bunks with grass sticking up above the surface of the water. In about 10 minutes I got back on the ski and attempted to take off but there was a bad vibration in the ski and it would not get on pad. I think I sucked some grass or something up in it but can not see anything in the impeller or wrapped around the shaft. Where else could the object be hung? Once you take the ski out of the water it revs up fine with no vibration. Any suggestions and how to get to the area on the ski would be greatly appreciated. I am fairly new to pwc's but somewhat mechanically inclined. Thanks in advance.