Can someone give me a technical explanation of what this actually means and what the fuel is doing?

I know it is caused by having too much fuel in the cylinder. How rich are we talking about? 10:1?

Thanks

 

 

10:1 is too rich and that'll do it . Washing rings out is when the fuel washes the oil film off the cylinder walls . Depending on boost you should be about 12.2-maybe high 11's . If you get it tuned right including ign. tables then 12.2:1 should be rich enough .