I wonder if it is really the prop. If changing props does not make a difference it points me in another direction. When I replaced my cylinders for Milleniums I had the rockers re-ground and checked the valve gaps writing the numbers down on a card. The manual allows something like 0.35 to 1.25 gap at TDC between the rocker and the valve stem. Of course the numbers were all over the place so by switching rockers around first switching the highest gap with the lowest and re- measuring, and repeat the process until all gaps are as similar as possible. This makes the valves all open the same distance and lets similar amounts of fuel mixture in every cylinder and makes a very smooth running engine. Of course, the hydraulic units in the tappets must be cleaned out and replaced if sticky. They must be unloaded so the gaps can be measured and the oil must be removed from the engine so they don't charge up while doing all the measuring and switching. Alan. N87333 N96496
