People remove the oil system cause they fail and cost you money. Mercury's have plastic gears on the v-6 cranks and the strip cause they drive a steel gear. Then it has NO oil and this will scuff the cylinders. OMC's on the other hand will normally OVER oil and cause coking of carbon on the rings. A bad thermostat will accelerate this but not allowing the engine to get hot enough to burn off some of the carbon. I have rebuilt many merc's and omc's for oil system failure. I have removed it on engines that are only 2 years old. So there is no wear issue as far as when to remove it. I will not trust a oil system. I mix my own and I know what my mix is. Plus the mercury system is only good for 6,800 RPM's and my next engine will be about 2,700 RPM's above that!!LOL. Gas actually has a very short shelf life especially with ethenol in it. I wouln't leave it in for more than a few weeks without stable. If you have ethenol in your fuel and your engine has carbs, they ususally have drains that are easily gotten to drain. THe ethenol will eat aluminum. Hope this help you.
