I had a similar problem with a Mariner 90 (albeit a slightly older one), that struggled on tick-over but was fine at revs. It turned out to be the diaphragm in the fuel pump that had given out. Should have been a rubber membrane over a wire mesh but the rubber had disintergrated completely. Net result was that engine was flooding slightly at tickover, but at revs when more fuel was needed then extra was used up.
Local service agent suggested the membrane should be replaced as part of service and he'd not seen one last much longer than 5yrs. Given yours is a 2002 this may be the cuase
(Apols for spelling ?? - too many peronis