Number 4 spark plug oily

[Gnasher]

If the plug is getting wet, the fuel is getting into the cylinder, in which case you need to check for a spark at the plug.  If there's none, put the plug into another cap and check it again, if there's a spark it's not the plug, check the cap, do the same as with the plug.  Go backwards up the high tension circuit, if all ok check the low tension.


Now it's also still possible it's the carb but it will be the pilot circuit, or the enricher circuit is stuck open.