Not sure if you tried a maximum lean, full power run to clear the fouling... But while at 1700rpm, lean slowly until you get a stumble, then rich until it smooths out, then apply full power for a minimum of 1 minute. If you have EGT, lean for peak at 1700rpm. This is an almost surefire way to clear fouled plugs on the O-200. I have employed it in the past, and the only reason it has ever not worked is if the issue is elsewhere in the system. Cheers!

This is the first video of yours that I have watched. It was so well done that I subscribed and intend to watch your others. I noted that you lean as needed, so I'm going to throw something out for you to consider, check, and verify. The O-200 seems to regularly (when sitting idle for awhile) allow oil fouling to occur on the lower spark plugs. Most of the time it will be very apparent which plug is going to be the consistently "guilty one". There will be obvious oil on the plug. Assuming that the plug really is still good, all that is needed is a quick cleaning. Gasoline and a nylon brush will get it clean in a minute or so. Dry it off. Install it. Run a regular mag check before putting the cowling back on. That would be an excellent and helpful video for you to make, too. Good luck p.s. Check the plug on the pilot's side, nearest the fire wall first.

Bummer. About 2 months ago on a x country flight About 75 nm into it my C150 started losing rpm gradually. I was at 3500 ft. I didn't recognize the cause immediately and with partial power I trimmed it for best glide and actually declared an emergency. Luckily, I finally realized it was carburetor ice. At 2500 ft I turned the carb heat on and got full power back in 30 secs. I feel dumb and mad at myself for not recognizing the issue right away. It was a good lesson.

Bummer!! Been waiting for a new video. I’m a Commercial/Instrument rated pilot who hasn’t flown in 8 months so I’m living vicariously through you! LOL. Looking forward to the follow up!

Don’t pull the cowling yet. Full power and lean it out. Gotta be full power to knock that lead off! Full power and lean will clean them plugs off 99% of the time. Blue sky’s

Good Evening Sir, like you said so well Safety First 👌👍😇Keep Uo Your OUTSTANDING videos Sir and I can't wait to see your investigation repair video Sir Cheers 😇👍👌🍻

bummer! hate those days. do you have per-cylinder temperatures?

Whoa! I could see the vibration in the camera in the cabin! I lie the addition of your wing-mounted camera.