I am the owner of an Evinrude E-TEC 115 HP, year 2006. Until recently it was doing great, always mantained by a cerified dealer. Since two weeks ago it's experiencing a weird failure: engine starts perfectly and performs OK up until 2,000RPM but everything onwards is troubble. When I reach 2.000 and keep pushing up the handle it does not increase power nor speed. Only with the gas lever at maximum, after a while it starts gaining some traction and then suddenly goes past 4,000 (and around 28 knots). Once it's there it works well but obviously I can't always go that fast. If I try to lower even the least bit it inmediatly falls down below 2,000 again. Nothing in between is posible.
My dealer's mechanic checked the gas circuit and all injectors are functioning OK according to the computer. He said it must be an issue with the exhaust valve that requires dismounting the entire engine. I am hoping for something simpler. Any suggestion would be very welcome!