Spark Plugs

[Fossenrf]

Changing spark plugs in my new-to-me 2002 Outback LS and want to get thoughts on the old plugs. I have no idea how old they are so I want to swap them anyway, but these look pretty dark.

The thermostat was stuck open when I purchased the boat and temp gauge would only get to about 130. The thermostat has been replaced and temp is now 160. Would the lower temp cause this coloration? It looks wet on the plugs, but appears dry when I wipe them off onto a rag.

[Holdmybeer]

They look a little rich. A cold engine would run rich naturally so that would explain that.
Nothing looks off based on the Plugs you have pictured.

A couple look dark like you have some oil blow-by. If you were worried, you could check compression to see what your range is on all 8 cylinders. Doesn't look unusual if these haven't been changed in many hours of use.

[zabooda]

If you don't have engine issues, I would recommend replacing the plugs and checking them at the end of the season. Be sure to get the correct plugs that are listed for that engine.

[MJHSupra]

Check the wires and cap too if you do not know the maintenance history.


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