By Dean Larson

Back in October of 2020, I pulled the trigger on Harbor Freight’s Central Machinery ultrasonic cleaner, and I’ve been using it pretty regularly since. I wrote an honest review of the tool after the first few uses (which you can find here), but in summary, it worked really well… on small things. The limiting factor of course was the size of the cleaner, 2.5 liters in this case, which means that even the Zenith-Stromberg carburetor from my Triumph Spitfire prevented the lid from shutting. It’s been about five months that I’ve been using it, just long enough for a long-term review I’d say (in the world of Harbor Freight tools), and that’s convenient because I’ve recently experienced an odd failure. If you didn’t check out my initial review on this tool, I urge you to now to get the full story, as I’m going to keep this review to the point. And that point is predominantly how I’ve used this ultrasonic cleaner since, and what went wrong.

Risking my shred of auto journalism credibility, I’ll admit that I work on more small engines than anything, mainly motorcycles, snowmobiles and other small two-strokes. So this tool has been great for those projects, since the carburetors are much smaller, and fit the 2.5-liter cleaner well enough. Ball parking it, I bet I’ve cleaned 50 carburetors with this cleaner this winter, and I think I’ve only changed the solvent a handful of times. In the last couple rounds, I had started to use a slightly stronger solution of Simple Green Pro HD to water than my original 1:3 ratio, and I achieved really nice results with little effort. Simply give the parts a good once over with brake cleaner and a brush and toss them in. The size of these parts means that the lid doesn't always shut, and sometimes you have to rotate them to get a full cleaning, but I've been satisfied overall with its performance for the money.

But I unfortunately need to disclose that that the Central Machinery ultrasonic has failed now, and not exactly in the matter you’d expect. See, many folks online complained that their cleaners failed as a result of solvent getting into the inside of the unit where the electronics reside. (For that exact reason, many people will advise that you seal it up with silicone right away to prevent this from happening if you overfill it.) But that’s not what happened to mine. Best I can tell, my little ultrasonic may have overheated, causing the plastic tray to fold up into the shape of a taco, and causing the ultrasonic power unit to behave erratically. The unit still works today, but sounds much different, and I don’t think I’m getting the same performance out of it.

I can’t entirely blame the unit itself though. I think I may in fact have had the heater running too long after the solvent partially froze last month when we experienced a few weeks of sub-zero temperatures. Yeah, it’s kind of strange that it didn’t shut off before damage resulted, but it is what it is. For now, I plan on straightening the plastic tray with a heat gun and continuing to use the cleaner, albeit with decreased performance.

But I know what you’re really thinking; was it worth the $85 gamble? I'd say it was. I cleaned so many carburetors with this thing, and a friend even paid me $150 to rebuild two of his carbs. So the cleaner paid for itself pretty quickly, and it’s also helped me to stop buying brake cleaner in bulk. It’s also worth restating that the cleaner didn’t really fail under normal use, and I’m probably to blame for the failure. With all that being said though, I don’t think I’ll replace this one with another one of the same size. After seeing how great ultrasonic cleaning is, I’m already ready for a bigger model, something that can clean a four-barrel carb or larger.

So in closing, I’ll stick with my earlier claim that the Central Machinery ultrasonic cleaner is a great choice if it’s your first cleaner, or if you have tons of small things to clean. It’s cheap, easy to use and heats up quickly. But for my next one, I’m thinking bigger is going to be a lot better.