RaysonCraft and mtruex are on the right track. If you can pop the throttle and the engine accelerates cleanly with the boat out of the water, you are to lean. The engine should stutter when accelerated without a load. Unless you have contaminated your fuel with solids and the filter is partially plugged I doubt that the filter is contributing to the problem. To much prop will load the engine and prevent acceleration also. Did you just grab any old prop or did you pay attention to the diameter and pitch to be sure the engine can handle the load? My guess is that the wimpy engines they put in RTR boats can't take much prop. And excuse me for correcting you but we do not run gas. We run a Nitro methane, methanol and oil mixture we call fuel. Two entirely different combustables.