ive got an evinrude 35 3 cylinder, power tilt ect. i had a problem today
with it, that when i put it into reverse it went forward instead of
backwards

Rich... Check the trunion of the cable at the engine (the portion of the cable
that clamps at the engine). There's a possibility that it was not secured
properly and has slipped out of the clamping area.

Joe (30+ Years With OMC)