Borescope Inspection of the Inside of the Cylinder of a Honda Lawn Mower Engine
This borescope inspection video is of the inside of the cylinder of the Honda engine of my Husqvarna lawnmower. It's about five years old and has been used about once a week, on average, during the warmer months.
I must say, I was surprised at the amount of deposits inside the cylinder, especially by the valves. I always use ethanol-free gas treated with STA-BIL, and I add some Techron to the last tank of gas at the end of every season and let it run itself out of gas. I also use high-quality synthetic oil in all my machines. So I was a bit surprised that the deposits are as heavy as they are.
In fairness, however, the engine still starts on the first pull and runs fine, so the deposits aren't affecting the engine's performance. The first sign of that is usually knocking caused by the effective reduction of the cylinder volume, which increases the compression ratio and causes detonation. That's not happening.