What is this?

[vic008]

Thought it had to be oil coming out of injector. Get rag to clean but no, won't budge. Like a dried varnish. Bit more of it than a week ago

 

[Aussie farmer]

Makes me wonder if it's spilt or dripping there tar or sealant , the injector to the left seems to have a bit up on top of the lug.

 

[CAPTAIN FANTASTIC]

If it is like tar then it is from a leaking injector. The injector has to be removed; clean the thread and seat and fit a NEW washer. It is much easier to remove the injector with the engine hot.