I have a 60 hp mariner bigfoot.It starts fine & runs great for about 45min. At wide open throttle it slowly starts losing power until it dies out completely.If you throttle it quick it will go to full throttle ,but just to 4400 RPM when it usually runs at 5000.if you try to back off any at all it dies to 3000.Sometimes when it does it you can activate choke & it will pick up but not to full W.O.T.I replaced fuel line,vents ok,spark ok,new plugs installed,& it recently had a new stator put in.After it sets for a few hours its good to go again.yesterday after it started doing it,I took engine cover off & there was a little water in bottom of cowling.I removed the airbox & in the bores of carbs it was milky looking.Where could the water be coming from & could this cause the problem.The cowling seems to be watertight from the top. HELP...its driving me nuts. Thanks