Originally Posted by muirdo
whats the biggest engine that you've seen on a 5m rib,running with 50hp johnson just now but need more power.I have old yamaha 90 2 stroke but would need a bit of work,just wondering if its worth looking for anything bigger
What's the boat rated to take? Quite a few Ribcraft 4.8s have had 70s installed on them, and of course the well known Avon Searider 5.4 can take a 90. I shouldn't imagine your hull is as well built as a Searider (although they look quite smart looking at the Arimar website) so I would tempted to go with something a little less than a 90 (depending on what the manufacturer says).
If the main issue is poor balance because of too much weight at the back, perhaps look at trim tabs or shifting some weight forward (or even just a bigger anchor to help trim it out).