2, A large one on the port side of the engine, white, and clearly visible with the cowl removed and a second small one tucked in behind the rear of the oil tank...move the wires out of the way, find the hose in that area and the filter will be attached. The small one is for the valving of the lower 2 cylinders and is a tighter/smaller micron filtering element to keep those valves from foreign debris sense they are more sensitive than the general engine fuel requirements.
Pull up a Mercury parts manual and they are clearly identified.
