Hello, I picked up a 1996 Sundird Spirit 170 with a 1996 Evinrude 88 SPL at a good price. The boat was in good condition and did not need to much. Got the boat running and did some basic maintance to it. Took it out and it did really well, gets up on plane fairly easy with 2 people and struggles with 4 or more. Question, I could only get about 4200 RPM's all trimmed out and was running about 34 MPH (boat speedo). Motor runs great with no problems and I am happy with the speed but I want to make sure I am operating the engine at the correct RPM. I put a new tach and rectifier on the boat already so it should be reading correctly. I am told I should be getting about 5500 out of her and that the prop may be the problem. The boat is a 17 ft and I am not sure the weight.The prop that is on there is not the original one to the boat and I have looked and looked and cannot find a pitch on the prop anwhere. The prop appears to have been reworked and ground on and is also a little chewed up. I dont know where to start with what to replace it with. I did replace the spark plugs today, they were so worn that the gap was about 70 thousands. Maybe that might make some differance.Thanks
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