I replaced my Perkins 4-236 with a New Westerbeke 90A4. It was a hard decision, but it was the best decision. That new Westerbeke runs like a watch. Everything in new. I'm not dealing with all the little items that are old and could break. The cost was about $3000. more that rebuilding the Perkins and the transmission. It did take some work to change the engine mounts. I would do it again.