I had about 450hrs on my FORMULA when I did the engines (HP500'S). All looked good inside except the rear exhaust valves, a little corrosion. The boat was used in mostly fresh water, but went to the Keys several times. On my 41, I have the Kieth Eikert prelubers and use them each weekend to oil the engines BEFORE start-up. I don't know if this will actually help, but at $35,000.00 for each engine, I ain't taking no chances. Besides, you can plug in a hose and change the oil real quick. The difference between KE's deal and MasterLube is the KE is 12volt where as the Master lube is pressure activated. Once the button is pushed on the MasterLube you only have the stored pressure to lube the engine. With the KE when you flip the switch, you can build oil pressure and hold it for as long as your battery will run the pump, and you can change the oil with the same pump. My vote is for the KE preluber, but what do I know, I have one of those antiquated V-Bottoms that everyone thinks is so slow.