Re: loosing power
Perfect world, carbs stay clean forever. Eventually float valves/seats wear out. Real world, get some debris in the fuel, or some other random act, carbs need rebuilding. If it's been like that since the last carb rebuild, could be they didn't get cleaned out good.
Knowing your RPMs (and compression) would be helpful in figuring out whether you're getting all the power you should, and if a different prop would improve your performance. Tach is a real handy diagnostic tool. google tinytach - they have a pretty cheap digital inductive tachometer.
Meantime, make sure your fuel tank is clean, no water or other contaminants.
Inspect the fuel lines for signs of aging, stiffness, cracks, leaks.
Inspect your spark plugs, let us know what they look like after idling: color of the insulator, any carbon deposits, fouling, gap, any silver flecks. They should be champions.
Check to be sure your carb throttle valves are parallel and horizontal (but not beyond) at WOT.
Inspect the prop for any damage.
Compare the position of the anti-ventilation plate to the keel - should be about even, or 1 to 2 inches higher.
Power trim? If not try moving the thrust rod out a hole or two.
oh yeah, almost forgot, check out the "Engine FAQ" section of iboats, look for a thread with "Decarb" in the title............
