rich/lean

[RCManWithAPlan]

I have a redcat rampage xt with a 32 cc engine. Break in is complete. Lately it's been running rich. There is hardly no smoke though. But it sounds rich to me like it's choking up on fuel . The spark plug fouled out and i had to replace it. I'm using a premix fuel+oil 25:1 ratio that is high octane rating could this high octane rating cause a rich mixture that requires a hotter spark plug? I'm using the stock cmr6 should i switch to a cmr5

 

[Phill2]

Try the settings on the chart and fine tune from there.