Black electrodes

[michael hunter]

Tech
What brand of plug are you running? Looks like a rich condition. Is that after a day on the lake or after a long period at idle. With out having any running problems I doubt its anything to worry about.

[Irish_Jack]

Hey Tech,
If it was me, I would be taking a peak under the distributor cap and looking for any major carbon tracking(black charcoal-like streaks). If you see any, replace the cap and rotor. The cause is high resistance in the wires. This will make for a cold spark condition allowing for carbon build up. Replace those too along with the plugs. Make sure the engine is running up to temp. Stuck open thermostats will cause cold combustion chambers and fouling...
Cover your basics first... Do a compression test warm--should be 135 to 145 with out any huge variance. Spark plug gap and type are super important... Also make sure you don't have any clogged idle passages in your carb. At an idle there should be no fuel bubbling out of the venturi spouts on the primary barrels. These common problems usually won't cause noticeable misfire until they get really bad. If you have any questions let me know...