I bought this mower used 4 yrs ago. No tags or #'s on it. Went to scags website, but the oldest model they list is a 1990, and mine is older. Its a scag, 48" hydro walk behind. Manual blade engagement, and NO safty levers on haldlebars - just 2 clips you clik on to keep it in nuetral. So if you let go, it takes off full speed! Pretty sure its from the late 80's. Trying to find a service manual & parts diagram for it. Any sugesstions? A website? Yes its unsafe, but I cant afford a new mower, and after 20 yrs, it still cuts awesome.