Ultrasonic cleaning of carburettors

[Simon B]

I have borrowed an ultrasonic cleaner to clean a newly acquired set of PHH E3 carburettors.  I’ve ordered some carb cleaner and having cleaned the outside of the carbs the old-fashioned way with petrol and carb cleaner I was going to use an ultrasonic cleaner on the body and associated parts for a thorough clean.  However, these carbs have sealed or shielded throttle spindle bearings and as they appear to be in good condition, I was not planning on removing them.  I’m wondering if I can dunk the carb body with these in place and then force some grease or oil into the bearings afterwards?  Has anyone any experience of putting partly assembled Solex or any other carb with roller bearings in an ultrasonic cleaner and did they turn out ok?  Is there anything else I need to be careful with when using an ultrasonic cleaner on carbs or small parts?

Any advice would be appreciated, regards Simon

[lancialulu]

I cannot answer about throttle spindle bearings but a cautionary word about random small brass plugs can fall out of the body and or carb top and get lost before realising. Depending in the ultrasonic cleaner they should still be big enough not to go down the drain. It is recommended to clean at c50degC and that is the prblem

The 35 bodies being Mazak will also go a darker grey a bit. 42's come out lovely apart from the carb tops which are also Mazak

[Simon B]

Thanks Tim, I'd heard about carbs going darker/black in ultrasonic cleaners and thought it was just down diy cleaning mixes. I contacted the supplier of the powder type ultrasonic carb cleaner I have on order and yes, they have had the odd report of it turning carbs black! The premixed they sell had not been a problem but the powder type was bought-in, and a different product which they were thinking about discontinuing. I don't fancy using either on the Mazak castings and will stick to petrol or solvent carb cleaners. I will just use the ultrasonic cleaner for the brass jets.

Thanks again Simon

[andyps]

I used a small ultrasonic cleaner for all the brass parts of my Solex carbs and they came out really clean. I think I also put the carb top (and maybe the bottom part which holds the diaphragm) in the cleaner and they came out fine - I just used the generic ultrasonic cleaner fluid mixed with water.
In relation to the bearings it probably depends on how the bearings are lubricated originally, if they are open ones the cleaner shouldn't make any difference but I would guess they have some sort of seal and the risk is some fluid getting past the seal and not drying out, or being able to be lubricated properly afterwards.

I'd like to add an additional question if anyone can answer - I've got a spare pair of carbs I want to fully rebuild and as my ultrasonic cleaner isn't big enough to put the bodies in I wondered about having them vapour blasted but not sure if that would be too much for the Mazak. Someone suggested just putting them in the dishwasher as a good way to clean them so any advice on what is best would be welcome!

[Simon B]

Andy, I would be concerned about the glass beads or whatever abrasive media is used in vapour blasting blocking the small internal passages.  If you kept them assembled and covered the front and rear flanges, I think you would get an excellent finish on the bodies, ideal if yours have some corrosion to start with.  However the blasting would also likely remove the zinc plating from fasteners so either use temporary or replate/replace.  Dry ice or soda blasting are other options. I did experiment briefly with an accelerator pump body in the ultrasonic cleaner, however it was definitely going darker grey and had an etched appearance so I didn’t pursue.

My carbs were pretty good condition so I just used lots of solvent carb cleaner worked in with a small paintbrush, a wooden skewer for awkward corners and a soft small stainless brush on any light corrosion. They look fine and perfectly adequate for my purposes. Before and after pics below.

I also managed to persuade some grease into the sealed roller bearings these later carbs use. I very gingerly clamped a brass plumbing stop cap with a grease nipple fitted onto carb body around the bearing and forced some grease through.

[Beckerman67]

 I had mine vapour blasted a while back. They needed some thorough de-gritting afterwards though!

 

[andyps]

Thanks for the replies. The guy I've spoken to who does vapour blasting thinks he can mask off any areas which might be an issue, cleaning them out isn't as much of a concern to me as whether it might wear something it shouldn't.

The carbs which are on the car have been rebuilt and I used my small ultrasonic cleaner for many of the smaller components without issue, but couldn't get the main body in the machine I have, hence thinking of an alternative for another pair of carbs I have (I'm not happy with the ones on it currently).

I might try the dishwasher first, however!!

[jus]

Be mindfull of dishwasher salt and the effect it can have on aluminium alloy.