Plug analysis?

[nola mike]

Went to winterize the 4.3 last weekend. Decided to check plugs while in there. Kind of strange. Overall ok I think, but #3 had me concerned. Looks steam cleaned on 1 side, and had specks on the electrode. Worried about pre detonation but thinking more likely salt deposits. They didn't seem to be ferrous fwiw, though a tiny amount. Compression was 135-152 on a cold engine, #3 was 147. Thoughts? Planning on borescoping and getting an oil analysis, looking forward to the oil analysis (block had at least 200k when I got it and has probably 500 hours on it during its new life), running T4 15w40 since I got it.

 

[alldodge]

Maybe a bit lean, but don't see enough to worry right now. If boat will run hard for a few minutes, slow and stop without long idle than recheck that plug would provide better insight