When you unclogged it what was the obstruction ? I had a similar problem on my 18 month old Suzuki last week, but once I cleaned it out it was a combination of what looked like white grease mixed with a bit of sand and shellgrit. Not that I've been ploughing through sandbars but yeah the intake does pick it up in shallow water I suppose. I left the tail off for a bit and flushed the motor to make sure all the crap was clear.