Repowering means no four strokes for that boat, a pair of lightly used HPDI's or Optimax's would be your best bet, anything heavier and that boat will sit too low. You might see a 15-20% savings in fuel a season with newer engines, but unless yours are on their way out or you use the boat 30+ trips a year, its likely they would not pay for themselves quickly. Even if you spend 4k a year, you'd save maybe 1k a year, twin used engines will likely cost you 15k for the pair, more if they are new or barely used, that means you need to use them 15 years to pay them off. Unless you have a reason like more range for offshore trips, I'd say keep therm and run them until they become money pits, then repower. We repowered our 1989 Grady, at the time, the original engine was in for work every 3 months, we knew it was time and we were sick of losing time during the year. To us, the reliability was more important then the cost, after having the engine on the boat 8 year, I doubt it has paid for itself yet, the engine cost us almost 15k new, but nit did provide trouble free seasons and since it is now up for sale, it will bring in a few more bucks, we will likely break even in the end. To see if repowering is right for you, figure out what you burn a season and see how much you will likely save, then weigh all other reasons and see if it fits your budget well. Also do you plan to keep the boat a while, if you plan to keep it less then 5 years, I'd save my money and invest it in something else when the times right, if you plan to keep it for a while it might be worth it.
