Posting for a friend that purchased a nice sea ray with a 4.3 from and older owner who had this problem for years with this boat. Idles great and runs up to 2200 rpm only to bog when throttled up. He did a tune up and the usuall lower end goodies. He took the boat for spin the other day and was surprised to go from idle to full bore and it ran 50 mph for a couple miles and then he throttled down.Again next time trying that it only bogged and would not plane.???Any ideas