I think that your memory escapes you (or you are a bit weak). The 4hp Yamaha is a 4 stroke with FNR and with built in tank (and its a long shaft). I have lifted it and it is very light compared with other outboards. There is no other 4hp 4 stroke made with FNR that I know of that weighs less. If you can find one let me know. The 2 strokes are a lighter, but no where near 30#. My father had a 4.5hp 2 stroke Mercury outboard that he bought new in the 70''s and it was much heavier (they were made of all metal back then). Maybe you''re thinking of 30kgs--big difference (~2.2 factor). The 4 stroke, although a bit heavier, has much better fuel
efficiency, is whisper quiet, and doesn''t smoke. Being a sailor, I like these qualities.