I have a 1979 mercruiser 898 with the pre-alpha outdrive. Recently my lower unit has been making vibrating noises when I start it up. A few weeks ago the prop on the shaft was loose so I tightened it up but it didnt make any difference. debating if I want to take it apart or not and see wats wrong and maybe rebuild it. if not, I was gonna look for another lower unit. next question is, are all pre-alpha lower units the same? can I jus find one and replace the impeller and throw on my prop, install and good to go? the gearing for the outdrive should b in the upper unit so I should b fine correct? or wrong? thanks for the help!
