For what it is worth, a rich condition will cause incomplete combustion, this will cause raw fuel to acumulate on the cylider walls AND incomplete combustion of the traces of oil that will find its way past rings and valve seals, (even a "tight" engine will have some oil get by).

So in other words, a rich condition will cause the acumulation of "heavy" less volitile components of gasoline (looks like oil) and oil in the combustion chambers, especially in the absence of long (good hot) runs of highway driving.

Thus my advise, fix the rich condition... IMO once this is done, the oily plug problem will go away at the same time.

 

Thanks guys. It is for sure not the valve covers. The engine is totally clean. I thought it may be from the rich mixture, I am just trying to rule things out as I tune. I have been asking guys questions for a while about the carb, so I just want to make sure there are no other issues before I tune the carb. But it is not the valve covers. Thanks for all the input.