Boat engine spraying grey goo liquid at carb.?

I have a 2003 GMC omc 4 Cyld. It ran fine for about 40 minutes, then bogged down at full throttle to about 10 MPH. Normal cruise speed is 40. After awhile the engine started spraying a grey goo liquid at the tube entering the Carb. at the top of the engine. I had to puts back to the marina at 10 MPH and the liquid goo spray got worse and worse. A piece of filter then came out of the tube, and the engine started knocking real loud. Then it kicked into 40 MPH for like another 5 minutes, then bogged back down. This is a real new engine and only has 300 hours on it. Any help? Does the knocking concern anyone? Oh...and the Oil pressure never dropped, and the engine temp. never went up! Any help would be great! Thanks so much!