Rough Idle and smoking

[supersluice]

I have a 2000 vmax VX225TLRY and I have a couple of issues. First while idling with the motor trimmed down all the way the motors starts to idle rough but if I trim it up until the engine is level it idles normal but I seem to be loading up on oil and as I go to WOT it starts to feel loaded but then blows it out and takes off great.
Second, after going to WOT the engine runs great but after about 10 minutes or so the RPMs come down to about 4800-5000 and the boat slows a bit. The motor still runs good and stays in that RPM range and I have no other issues with the engine while running.

Thanks for any input.

[boats.net]

Run a compression test to make sure engine is in good shape, check that all cylinders are firing, check fuel pump diaphrams, remove and clean VST, may need to have injectors cleaned