To start with,adding more fuel doesn't lean out a mix,it makes it richer....Air can't mix with oil,so the more oil in a mix,the more parts per million of air is mixed with fuel...It may smoke more with more oil,but the cooling properties of the fueldrops off dramatically...You need to get an accurate way of mixing fuel and mix it at 32:1 with a good quality oil....No outboard oil from one of the major chain stores....
Have you checked the battery? I know it's turning it over,but I have seen the 350 get a very weak spark because of low voltage,even though the engine still turns over with the starter,and the engine will not fire off because of it........
Hoodlum