Old Project Farm using water to clear out his mower's carbon deposits was also a 'fave' of mine. You have to laugh at what some of these Yanks will do.

Scotty Kilmer's old school (he's going deaf [he is approximately HJ's age], hence why he always speaks loudly) and hates a lot of stuff about modern cars. His fix as regards sticky (hydraulic) power steering helped my car work better.

He's handy for the small to medium sized jobs for those willing to take the chance in doing DIY maintenance, assuming you have all the tools and your car is reasonably user-friendly in that regard. There are some DIY jobs I haven't tried as my car's specific sub-model has a more difficult to access parts for the jobs I want to do (cleaning the MAF sensor, EGR and throttle body).

I don't recall using significant quantites of water to clean the inside of an engine when actively running it being in the user manual...

If I recall, Project Farm nearly destroyed one of his mowers by doing this in one of his 'experiements'.

Gosh a Dwell Meter....that took me back to setting the points on my first cars then setting the timing by draping a coat over my head so I could see the timing marks with my barely glowing neon timing light.

I don't have a dwell meter. Probably hard to find now, especially here. I had a Gunson one in the UK but I dunno what happened to it.

I'm thinking I might try an oscilloscope to investigate the cars intermittent kangaroo impersonation. Apparently its possible to make one from an Android phone.

https://www.princeton.edu/ssp/tiger_cub/library/ignition_waveforms.pdf

Anyone done this?