I am having a problem with this engine bogging down. It runs excellent on the hose in the yard. Once I put it in the water, it runs brutal. Example would be once I put it into gear, I give it full throttle and it sound like the engine is drowning. It will not go above 1000 rpm. Compression is good. Had the Carb rebuilt back in October. I start it every week even if I don't plan to go out. It has new plugs, new plug wires, new water/ fuel seperator, new fuel filter. What could it be? Please help.