96 DT140

[old boat 61]

I bought a 96 boat that has this motor on it. The motor starts and runs fine except for full throttle.<br />The RPM's go up to 5800 and then drop to 5000. It acts like water in the gas so we put some drygas in the fuel and it still does it-the fuel line has a water seperator filter on it It idles fine,goes in reverse fine,-any ideas?<br />I also need new zincs, I noticed the rear lower one with a fin is almost gone. I checked Browns point marine online and they have many zincs listed for this year motor. How many zincs are there to replace?