1971 evinrude 125 lower unit

[hwcd24]

First off let me say thanks for all the help I have received on this site you guys have really been a great help. Now I am experiencing a new problem. I had my boat out on the water today (finally) and things were going okay, in the beginning the motor would not get up to full throttle but after about an hour the motor just kicked in started working like a champ. I ran it around the lake did not seem to have any problems and then all of the sudden my engine revved up but i was no longer moving forward. I shut the engine down pulled up the motor to check the prop. nothing appeared to be out of order so I started the boat up put it in forward and slowly increased the throttle. The boat will move kinda sluggish but still forward motion until I reach about 5mph then the engine just revs up again so basically I limped it back to the ramp. The engine stayed cool and the still seems to be running fine. I unscewed the lowest oil drain screw and milky oil came out. This does indicate a leak but I had the lower unit pressure tested and it checked out fine. Is there anything specifically that I should be looking at which would cause my problems? Thanks for any help I can get

[roscoe]

Sounds like you have 2 separate problems. The first one is obvious, you have a leak in your lower unit. Either the prop shaft seal, driveshaft seal, shiftrod seal, or the drain/fill screw gaskets are leaking. Drain the lower unit, fill with fresh oil. replace screws with NEW gaskets. Then run it a while and see if it still leaks. If it does, then one of the above mentioned seals is leaking.Second problem, engine revs up but no go. Your prop is spun, or your shear pin is broke (if your engine has one.)A spun prop hub can be fixed for about $40. Lots of info here on spun props. If you have a spare prop, put it on and try it. If it works, then have the original prop fixed.If you don't have a spare prop, this is the reason you should buy one.