I dunnoh ... I'm a firm believer in running what I have 'til it dies, as long as you're satsifed with the performance. I also don't believe that 25 ponies (coming from a heavier 4-stroke OB) are going to buy you much, if anything at all.
You could buy a ton of fuel for the $16K+ asking price to put new power on the stern :shock: !
Make sure you're propped correctly (WOT 200/300 off max RPMs, average load), treat her right, and decarb that 2-stroke every 50 hours with Seafoam or Deep Creep, plus change t-stats and full water pump service every 2nd to 3rd season, more depending on use.
Doing this, I got 24 years service from my prior OMC motor and she was still running when I moved up in horsepower, way up, 75hp, on my old rig.
Where your 23 is most likely a 21-degree deadrise boat ... if you're going to go up in HP, go to at least a 250hp to get some performance gains for your buck, IMHO.
