As time and miles pass, even the best-built and best-equipped cruising boats succumb to wear. Onboard equipment like rigging, sails, pumps, and other gear eventually require renewal. Unfortunately, there also comes a time when the auxiliary engine may need replacement as well.  Although most small, well-cared-for diesels can have an average lifespan of around 10,000 hours, there may come a time to think about replacement prior to that. Not all motors have been well cared for through their lives. Rust, corrosion, poor maintenance and general abuse can shorten an engine’s life. As years pass, replacement parts can become harder and…