I’m trying DOT3 brake fluid as a cleaner on my horribly complicated late 80’s car carb right now and it seems very effective. Since its not designed for that use, and I’m only a couple of hours in, I can’t rule out lurking gotcha’s, but advantages include:-
(a) Much less volatile, so you can leave it to soak-in and it wont evaporate.
(b) much less toxic, and ventilation isn’t so critical.(see above)
© water-miscible, especially useful if you wash parts (or the whole thing) in boiling laundry detergent, which was my standard procedure with motorcycle carbs.
(Dunno if I’ll try it with this one (which is a lot more complicated) though.)
(d) rubber-friendly in general, and specifically, hypodermic-syringe friendly. I use syringes to blow out small passages/jets (formerly with water/detergent). You can’t do that with carb cleaner because it attacks the piston rubber.
(e) Free (if you use used fluid) and almost free if you use unused fluid since it has a limited storage life once opened.
EDIT : This assumes you change your own brake fluid of course. I was forgetting the generally “white handed” nature of foreigners here. ENDEDIT
Doesn’t repel mosquitos though frown.
I suppose not many people have carbs on their cars anymore so it isn’t of much contemporary relevance (“Ducked Developments : Solving Yesterdays Problems, Today”) but there are still quite a lot of carbed motorcycles about.
I’m told that current DI car engines suffer from coked-up intake valves, because there isn’t any petrol in the intake tracts to clean them, and the blowby from the EGR/crankcase ventilation system makes them dirty (I’d expect it to have been happening to diesels for ever, then, but dunno if it has)
Perhaps a soak in brake fluid, followed up by a hot water spray in a running engine, might help with that too.