Re: You are not the only one!
Andrew;
I found this yesterday on iboats. They have a write up for Marlin's. For the 1973 Neptune is writes:
http://www.iboats.com/Marlin__Neptune__1973/bp/64b54981r0
"1973 Marlin Neptune
This Marlin outboard sports runabout has a fiberglass hull, is 15 feet long and 71 inches wide at the widest point. The boat weighs approximately 800 pounds with an empty fuel tank and without any gear or passengers. The maximum horsepower we have listed for this outboard boat is 75 hp . If repowering you will want to verify the max horsepower for safety and to make sure your insurance company will insure your boat.
Despite the fiberglass hull on this sports runabout, we recommend that the boat be kept dry and covered in order to preserve the value of the boat. Proper care and maintenance can help your craft stay nice and increase resale value. We have included some outboard engine information since a boat isn't much good without a good, reliable source of power.
Information on this page is provided to you as a free service of iboats.com. Because this information has come from many sources we can not guarantee its accuracy. Even if this information is the same as the original factory specs, boats are sometimes modified. Thus, for safety and other reasons, it is a good idea to verify information here to make sure it matches up with your boat.
Engine Information:
Boat Max HP : 75 hp"
Andrew:
Look at the write up of your model. My Marlin has a Neptune sticker on the port side towards the stern. Let me know what you find out.
ebry710
