New to the board. I recently bought a 1985 Nitro boat with Mercury 150XR6, the motor has a few issues but need to determine year of engine before diving in. Serial # 0G228702 Issue is rough idle and feels like a miss or hesitation at WOT can only get about 3700 rpm. We have done a link and sync, new filter and hoses compression is 120-125 all cylinders, timing was set. Now we get 4300 rpm but still idle rough and has the miss at WOT. Was told it could be reed valve but more testing needed to be done with a vacuum gage?
