Keith, I have also tries all of these various solutions and ultrasonic cleaners, but the best and safest by far is a "crock pot"/slow cooker with straight undiluted green ethylene glycol antifreeze. Leave overnight, brush off with an old toothbrush. It also is completely safe to allow inside the engine, it will not corrode the bearings, and, unlike ultrasonic cleaners, does not cause the bearings to be bounced around at ultrasonic frequencies. We use it to remove varnish from cylinder liners and pistons all the time. You do want to oil it afterwards, but it is not dangerous or rust-enhancing like water. I have done mufflers and tuned pipe headers that are *far, far worse* than yours, they come out shiny like out of the package with no abrasives.

Keith, continue to enjoy your work

Love the "admonition!!" text on the cleaner. An admonition sounds like something you'd get from your school head master or a pastor, not an appliance...

I bought an ultrasonic cleaner for cleaning old double-edge razors and gun parts, some ten years ago. Then I discovered it's great for fountain pens and eyeglasses and watch & clock parts, too. They're amazing devices. Every home (er, shop?) should have one. Kept mine in the kitchen for years, too. Good on ye, Keith. I rather like the bit of a turn the channel's taken to airplanes, by the way. Many thanks.

I always seem to learn something new watching your video's Thanks

Great information the engines came out looking like new

Just a thought Keith WD40 as used by everyone isn't a good lubricant as in time it "disappears". It would be better to use a maintenance spray that leaves a film of oil behind.

For your mufflers that are coated in burnt castor oil the best thing we found for RC cars was to cook them up in antifreeze overnight helps it come right off. Not telling you hoe to suck eggs but a good light mineral oil is good in the crank case some products like CRC contain acids that will eat into your bearings. Will be great to see it going though

Didn't even dawn on me that it had a case tap for tank pressure. Been a while since I've seen one like that!

Great result!

Helpful

I have had very good luck saving small engine carbs with the proper solutions in an ultrasonic cleaner. I did try some alternatives suggested by other techs and was not impressed. Maybe that is why I had a better success rate. You can use the solution more than you would think. I changed it every few weeks. Maybe a dozen carbs.

If you have a concern about the plastic parts then drop in a piece of scrap plastic. In my experience is that if the plastic doesnt soften or get sticky or change sheen it is probably ok even if they arent the same plastic. I think this is because all plastics are a blend of different plastics so if it has even 5% of a susceptible plastic it will be sticky or slippery.

For the silencers that were pitted. I wonder if a ziploc bag filled with lemon juice would be good in the ultrasonic? Vinegar might be a bit too aggressive.

Could I ask what make of Ultrasonic cleaner you have?

now with all these "brand new" engines, you will have to build some brand new aeroplanes to put them in.

What size is your ultrasonic cleaner? Looking to buy one but unsure what size is good. Of course ymmv but would still be good to know a data point. Your size look quite useful.

I have an ultrasonic cleaner beside the sink and a distiller. Nobody to tell me what to do! Which also means the place is a bit of a disaster :p

"E.D." engines... I expected a reverse girlfriend joke.