Yanmar Engine Problem

[J Clark]

I have a 31 FBC with Yanmar STPLYA 370's, with 412 hours on the engines.
I had the valves adjusted, turbos cleaned, I changed the oil, secondary and primary fuel filters and checked the belts and coolant, all seem to be OK. I took a trip down the ICW this past weekend, loaded with six people 220 gallons of fuel, luggage for the trip and ice, food, booz etc. Cruised at an average of 22 knots. Burned about 180 gallons of fuel on a 260 mile trip. Problem: The port engine's turbo would "whine" when the I got up to about 2500 rpm's, I could back down to 2300, and the "whine" was not as prevalent. I could sometimes run the engines up to 2500, and the whine would not start, but after a few minutes the "whine" would begin. Starborad engine ran perfect. Both engines were at the same temperature and oil pressure.
However, the port engines is smoking a small amount of grey/black smoke at cruise, it also is blowing the cooling water out of the exhaust.
The Starborad engine's cooling water is just a smooth pouring out of the water. The port engine's exhaust water is hot.
Any suggestions as to the problem, before I cal in mechanic.