2021 AR 195 - Spark Plug Queation

[Wick3d3vo]

Hi All, I started to winterize our 2021 AR195 boat (Houston, TX)....It has ~70 hours on it. That said, we purchased the boat used with ~60 hours from a reputable dealer as CPO in April of this year. However, the 10 hours that we put on the boat this summer season has questionable spark plug results when pulling the plugs this afternoon for winterization. The 1st 3 cylinders from the cockpit back all looked rough (similar to the 1st two pics) but the last cylinder closest to the ladder (the rear of the boat and the last two pics) is super lean. Any thoughts on what can be the issue?

 

[FSH 210 Sport]

To me the plugs look the same burn wise, to really read the burn one needs to look down inside the plug with a strong light. I’d wager these are the plugs the boat came with by the looks of the wear on the electrodes.

The big thing I see with the plug in question is all the corrosion on it, and that corrosion appears to be top to bottom. Im assuming this boat has been used in salt water? Have you been flushing the engine with salt away after each use?

Clean everything up and put a VERY light film of anti seize on the threads of the new plugs and run it.