of engine access as almost the entire floor of the pilot house can be lifted out in three sections. Front access is great as is the rear. Access on the sides is fine but limited by the width of the hatch which is about 30 inches. Once you get under the floor it wide open. The problem is height. Do you know if the Yanmar taller then the 4-108? It sounds like you replaced the boat and ended up with the Yanmar so you don't know if new engine would have been a direct replacement or not? It's good to know that your happy with the engine. Thanks.