The problem of spark plug combustion

912发动机工作正常，但火花塞很黑，请问出现这种情况的原因，如何处理

912 engine works normally, but the spark plug is very black, may I ask the reason for this situation, how to deal with it

We need a lot more information. Could be idling too much? Do not sit at low rpms for any length of time. How old are the plugs? Is this a 912uls or a 912iS? What do the plugs look like if you run the engine around 4000 rpm for about 5 minutes. Shut it down and no idling before you check the plugs.