working on a 1979 evinrude 15hp motor. has been running good. all of a sudden it will not shift in to forward. reverse works just fine. had to run 2 miles in reverse to get home.
Did you by any chance try to drain/change lower unit gear oil & may have taken out the wrong screw? If so this Phillips head screw is the shifter yoke pivot screw, & could be your cause if you did not get it back in right.