I have a 1979 15 horse johnson.Yeasterday I took it out after 9 months sitting,got it fired up but could'nt get any speed. noticed water oil mix coming out of holes just above the lower unit. Right behind the screw to add lub to the lower unit
Also water oil mix at the prop nut. The motor started to go fast for just a sec. then bogged down.
I started it with a water bra a month ago and it ran fine. Any suggestions would be well appreciated.
To me it sounds like you have a crack, seal leak, or leak around the input or output nut. I could be that there was an internal crack, and when you put the water bra on it forced some water into your lower unit lubricant. Then when you actually went to use it the big problems started.
From the way the motor speeded up and then bogged down it is very possible the lower unit gears lost the lubricant needed, and hopefully there won't be any damage.
The first thing is to find the leak, and that may mean a visit to the outboard service department. Unfortunately that isn't cheap these days. If this is the case try to find a good dealer that will give free estimates.
If I remember correctly that model of Johnson was a good one, like the old 6 h.p. that I have.
Good luck, and if I can be of any further assistance in this or other questions don't hesitate to ask.
Best of fishing,