I have a 1965 Evinrude 6hp model 6502M. This motor starts the first pull & will troll all day without a problem. When I go to run @ full throttle it will bog down. Quite by accident I found that if I raise the cover the rpm's increase and it seems to run fine. I have contacted 5 repair shops in this area and all of them are @ a loss. I do not have anything touching the flywheel that would cause binding.There are no unusual noises.There is no indication inside the shroud that exhaust gasses are being sucked in.The plug wires seem to be in great shape.I have a new head gasket, plugs, points, condensors, fuel pump, coils, thermostat & water pump. It is pumping a good flow of water and seems to run cool enough. I am running the required 50-1 gas mix using 100% synthetic TCW 3 oil. The magneto armature plate is set to spec as are the points and plug gap. The carbon was cleaned from the pistons & head when the new head gasket was installed.A can of engine tune was also run through the motor. The compression is 80 #'s on each cylinder.<br /><br />Any thoughts are appreciated.<br /><br />Cliff