If your pump is like mine it is a gear type (displacement style) pump meaning that nothing flows if the shafts don't turn. If you can't find your oil pump it is located between the oil tank output and the fuel inlet to the engine with a wye on the fuel inlet (pump output) side where it adds oil to the gas hose. Follow the hoses....its in the middle.
I had 3 bolts on mine to remove to get the pump out with one hose on the pump to remove. There were one or two more hoses attached or in the way to get to it, but I only had to open one connection. The pump comes straight out and on the other side is a gear sticking out. Grasp the gear and pull it out ensuring that if any washers, spacers, or anything else removable in the shaft's hole that could come out are also removed. On mine there was nothing but the gear and the drive shaft, all one piece of steel.
That's all there is to it. Put the pump back how you found it and be on your way. Don't need to do anything else but maybe write on your boat where you fuel up "1 pint of oil to 6 gal. of gas".
