A few weeks ago I noticed the plugs were a red colour:
We took the engine out on Saturday and popped the head off:
The engine runs really well and only burns about 50ml of oil a month
I'm using Penrite Classic Light 20W/60 oil.
The fuel is supposedly 89 RON 'super' unleaded - there's only the one fuel supplier over here now and I'm dubious about its quality - but we have to go with what's available.
Any ideas anyone?