You would prob get about 4-5k per engine if they are in good shape. You would not need instruments if you stick with yamaha, so you would be paying the remainder of the engine costs. You need to weight how often you are going to use the boat to decide if it makes sense to repower. If you need the extended range, that may be a factor as well. The 2 strokes EFI's will burn a little more fuel on that boat, but the difference is probably .1-.3mpg throughout your rpm range. Four strokes do not mean better fuel economy, but they are slightly better then the OX66 engines on fuel. Also, your 2 strokes will burn oil. If new engines are $16,000 each, and you get back $5000 per engine, your looking at roughly $22,000+ tax and installation. Are you going to burn enough fuel and oil to make it worth your money to repower that boat? If you are willing to spend that much money to repower, you have 2 alternatives, look for a boat with four stroke power that is roughly $20,000 more then the one you are currently looking at and save yourself the trouble of selling your engines and having the boat repowered, or buy the boat and run those engines into the ground, and when they are on their way out, then repower, by then there will be even newer technology and hopefully more fuel efficient motors. As much as I love my four strokes and agree it would be ahrd to go back to a two stroke, IMHO it would not be worth a repower unless the engines were in bad shape. Another alternative is to find low hour F250's for sale, but I'm not a fan of used engines in good shape, they shouldn't need to be repowered, and you never know what the previous owner did or didn't do with them.
