mate its a 1974 yanmar ysb 8hp ..thats all i know of it . in terms of the nuts,6or 8 there all out and I have dissembled the the four blots from the shaft coupling ..she's free of the housing but will not seperate from the engine .there is it seems something stopping her. Ithink its something to do with the gearshift assembly..thats all Iknow