Recently, my 98 Pro-V 200 locked up after many hours of flawless service. My mechanic replaced powerhead with a new, not remanufactured, powerhead. He also replaced water pump and cleaned carbs. I double oiled for @ 13 hours and followed the break in procedure to a tee. I've probably have run @ 40 gallons under normal oil injection since break in and installed new plugs. Prior to rebuild I ran 5800 rpm at 52mph on gps. Now it only turns 5200 rpm at 48 gps at proper trim. Same prop, etc. I thought maybe linkage changed from service work but mechanic said probably not, just run it some more and see if it improves. Just for info, mechanic is well known and respected, but I am still suspect that it may need some tweaking. Ideas?