Given the age of that boat and if it hasn't been done before, I would remove the oil tanks, check the tank brackets, blow out and reuse all the small lines individually, replace the small filters and put 12v to the motors and see if they are really shot. I would also disconnect and blow out the oil line up to the motor holding tank. Pour all the oil into a bucket and check for sludge in the bottom of the tanks which can clog up the filters and the oil pump motor. When the job is complete, run the oil through a paint strainer to catch any impurities that may have gotten in there over the years. If you have sludging issues, consider recycling the oil and starting fresh. Just did all that to my boat and custom built new tank holddowns out of starboard - never to rust again. arctek on this forum also makes a nice custom aluminum holddown. I ended up replacing both oil pumps and saved one as an emergency backup. There is a possibility that they were both pumping OK but since my floor is screwed and caulked down - I didn't want to mess with anything down there for a few more years. Possibly some overkill on the whole job but I like to eliminate as many future issues as possible when digging in to something like this. Let us know how it works out for your friend.