Hello, I'm looking at a 480CE powered 390 Motor Yacht. I've read a few horror stories on dropped valves, failed valve seats, totaled motors due to over loading/propping. I'm curious how many people here have had their props tuned or changed entirely to reduce engine load? The boat I'm looking at doesn't have the capability to report fuel flows so all I have to go on is its history of Cummins service, light loads and elderly owners. Obviously it's a big concern and I'm unsure if I should complete the sale.