I own a 90 225 johnson and have access to a 250 yamaha for a good price but after a few trips with the old 150's and coming home on 1 motor both times I just really think i want to have twins and according to the performance data spec sheet, that I assume was a original seacraft document, the 23cc that came with 115 omc 4cyl's had a top speed of 42 mph and those 78 115's were making 100hp at best at the prop. I know the 90's will work, and do better than 30mph, I was simply trying to get feedback from someone if there is any one that has had experience with small hp 4cyl john/evinrudes on a 23. And there is a 45lb difference between the 4 & the 6 cyl omc's and as I stated the boat went 40 at 4000 rpm's with the 150's that have a whopping 80 lbs of compression across the 12 cyl's and pipedreamsmarine is correct about the 150's making 120hp at the prop new and with 80lbs of comp. maybe 100hp granted the 6's even worn out will make more torque I am convinced the 90's will make 40mph wot and cruise at an easy 28-30mph