I have a 1994 22' Larson with a 5.0L V8 mercruiser. Changed main fuel filter, screen in fuel tank, checked anti-syphon valve on tank, and changed the filter in the line just before the carb. The engine idles fine, and revs normally when not in gear. Once in gear, still idles fine, but once it reaches between 1500 and 2000 RPM's the engine either sounds like it's about to stall, or it continues to surge up and down. Once past about 2500, it smooths out and runs beautifully for about an hour or two. It then starts to Bogg out even at full throttle, and only reaches just under 3000 RPMs. Not sure what to do. Another question, there is a small clear rubber hose going from fuel pump to carb, not sure what that is?
