At WOT I get way too much vibration from bent shaft on 1980 70hp Johnson on 1975 24ft Kayot...oh well the admiral doesn't like to go over 8 or 10 mph anyway. I need to figure out if a lower end rebuild is doable this winter without special tools or if the parts put it out of the budget. First motorboat, having lots of fun boating and fixing her up. I have to resist the urge to put any real money in her and save it for the big upgrade in a couple years when I retire. This is a testbed to figure out what I want/need and make my mistakes on something that won't brake my heart if I put a dent in it.
If you haven't already, Check boats.net for outboard parts. They will give you an idea about what a rebuild might cost. and yes you will prolly need special tools or a machinist son in law like I have to rebuild it!