Took my plug out today on my gp today and I noticed a bit of black crud round the cap and around the outside of the frame and side panel at the front.
The plug wasn't loose no leaks round it and its running fine.
Go easy on me still learning.
Cheers.
Possible head leak on gp
Take plug cap off and spray soapy water around plug whilst kicking it over. If you get bubbles around plug you have a leak. If this is only slight a touch of threebond or similar on plug can help
Should have said put the smear of sealant on plug threads. Dont go mad with it though.