Re: Reading RPM's
So your seeing higer RPMs than you normally do right? How long have you had the boat? Any chance it could be something as simple as cavitation? Kinda sounds like the boat was heavy. Any chance there was a leak or saturated floatation foam? Hard to tell but it is odd that it corrected it's self at high speeds. This leads me to believe it isn't a mechanical problem and more of a drag issue or perhaps a damaged prop. Here is why. If there was no slipping in the gearing (which you would easily notice) then there is no way for the engine to have noticeable difference that I can think of. If the link between the RPMs and the prop is good, its probably not an engine problem. If you had told me you cant get the RPMs up to the normal levels we would have all sorts of things to explore, but it sounds like you have good power. Perhaps a lower unit issue but again, there should be some noise or vibration. I have seen this when I have trash (weeds or fishing line) wrapped around the prop or when the bilge pump malfunctioned. When its the water or weight issue, the boat may perform almost normal at full speed in full trim and having most of the boat out of the water thus reducing the drag. One other issue could be what is in the boat. Any chance you rearranged something heavy in a different location that may make the boat bow or stern heavy?
