I have a 1977 Evinrude 115. We rebuilt the motor, new block and all. When put back together it idles great, in and out of water. We do not have an RPM gage so I cannot tell you what RPM I am at. But basically when the boat goes in gear and begins to get more of a load on it, it bogs out and quits. A couple of times I was able to get the boat to plane out and it runs great on the upper end, it was able to pick up speed fine. It is the in between lower RPM and higher RPM where it has trouble. I feel this is an adjustment but just need some tips on what to adjust.
