A little bit of lube leaks out of my 1965 merc 50 hp after use. Drips some, then stops?

Question

My 1965 merc 500 runs great. When I take it out, about 20 minutes later just sitting on the trailer, a little lower unit grease leaks out of the lower unit. I think it is coming from the little nipple place where you change the lube. There is no cap on it. Is there something greatly wrong with my engine, or do I just need a new cap? Thanks

Answer 1

If there is a screw missing from the lower unit gear oil case, and salt water got in there, those gears are "Toast" ! If it just drips from the prop hub, it is just exhaust oil dripping and no problem.

Answer 2

50 HP Merc has two screws on the lower unit. One at the bottom to Drain and one up top (12-18inches up from bottom) to open to let off the vacuum effect so it will drain. The prop shaft has a seal. If, it leak from the large shaft hole at the prop, it may need a new seal, or, just keep it topped off from time to time if it not leaking bad. The screws, if they leak, usually the bottom, you may be able to remove the screw and clean the area and see if it seal. Also it may have been "Cross-Threaded" and the cause it to leak. Use a "Tap" to try to straighten the threads and it should fix it. Also. if worse come to worse, put a little O-Ring Rubber on it. This not a highly technical part. All you want to do is stop it from leaking.
IF, it not leak from the prop or bottom screw, clean real well and remove the top screw and wait and come back and look close, the housing may be cracked. Sometimes if the engine left up in winter, rain gets water in the housing behind the prop and when it freeze you get a cracked housing. I would drain the lube and clean the area very well with some carb cleaner spray and sand away the paint. Then rough it up and use some J.B. Weld on the crack. It not under pressure and this may work. Silicon Rubber may work, but, I would try the J.B. Weld. IT HAS to be clean of lube/oil!