Cleaning Carbs, especially small ones

[bricol]

Its going to help if you submerse the carbs (or whatever you want to clean) and then rotate slowly all angles, all ways, to try to get all the air out, and cleaning solution into all passages. If the solution isn't in there, then the ultrasonics are not going to do anything - they need the fluid to be in there to work.

You do need the right chemistry to do the right job - and sometimes that does mean you need to spend some money. I would have recommended some mates of mine (my old bosses infact) but they retired and closed down last year. The tank and chemical they lent my mate did a perfect job on his webers for his Elan.

Vacuum chambers are good for drying awkward things - put them in, pull the vacuum, and the water will boil off at a lot lower temp. Used to be an option on some of the multi-stage ultrasonic cleaning machines I used to design.

 

[Ross365]

That's why I have been using my vacuum oven, as per post 6. First you have to degas the liquid by ultrasonicing it for 5 minutes before you put the carb in (in this case a small Dellorto, and a glass beaker of cleaner). Then put the carb in and swirl it around and do all I can to get as much fluid in and air out. Then I put the beaker containing the carb and cleaning solution in the vac-oven and pump the oven down. Initially nothing happens but as it gets to a better vacuum, you can see a "belch of bubbles" start as air that was still in there finally comes out. When no more is coming, let it back down to atmosphere and transfer the beaker and contents to the bath.

As mentioned earlier, if it's petrol residues you need to shift, solvent like acetone or MEK may be the way to go, but some other contaminants (especially solid particles like rust) may be best dealt with using water and a good cleaning additive. However, I do sometimes think that it can be a pretty thankless task.

 

[MCKDAVID]

Aspen 2 and 4 is the answer, expensive but worth it in the long run...I've not had any problems since I started using it in my chainsaws or lawn mover...

agreed it's a good solution for low volume user, does get expensive quickly though, mind you a strip down, and rebuild carb kit is not cheap either.

Still think the best solution run them regularly or go for the electric / battery powered ones now, unless you really need the power / longevity of petrol powered...

 

[MCKDAVID]

That's why I have been using my vacuum oven, as per post 6. First you have to degas the liquid by ultrasonicing it for 5 minutes before you put the carb in (in this case a small Dellorto, and a glass beaker of cleaner). Then put the carb in and swirl it around and do all I can to get as much fluid in and air out. Then I put the beaker containing the carb and cleaning solution in the vac-oven and pump the oven down. Initially nothing happens but as it gets to a better vacuum, you can see a "belch of bubbles" start as air that was still in there finally comes out. When no more is coming, let it back down to atmosphere and transfer the beaker and contents to the bath.

As mentioned earlier, if it's petrol residues you need to shift, solvent like acetone or MEK may be the way to go, but some other contaminants (especially solid particles like rust) may be best dealt with using water and a good cleaning additive. However, I do sometimes think that it can be a pretty thankless task.

interested in trying this process, already have the vacuum pump (fridge type). Any chance you could stick up a few photos of your set up, what you use, so I can blatantly copy it and give it a go... thanks

 

[zzr1200]

agreed it's a good solution for low volume user, does get expensive quickly though, mind you a strip down, and rebuild carb kit is not cheap either.

Still think the best solution run them regularly or go for the electric / battery powered ones now, unless you really need the power / longevity of petrol powered...

To a certain extent I'll agree, my strimmer a cheap Far Eastern one started up 3rd pull after it had been sitting for over 10 months (due to long term illness).

My lawn mower now starts 2nd/3rd pull after been left in the shed over winter, a jug of Aspen 4 lasts about 2/3 years, so is worth the lack of aggravation.

The chainsaws may not be used for 2/3+ years before their fired up, one hasn't been used seriously for about 8 years now it gets fired/run once a year, but I do have a few, so I have a choice to play with.

As for the cost if you consider todays price of 5ltrs pump fuel plus a good quality 2 stroke oil (£10.00-ish), £21.00 for a 5ltr jug of Aspen 2 it's double, but it'll cost more than the saving using pump fuel, to supply and fit a carb kit plus down time.

For commercial users pump fuel is the way to go, but for a home owner/low usage gardener who does a bit of tree trimming, a no brainer in my world.

As for battery powered tools I'm not a fan of them, I do have battery drills, screw drivers and an angle grinder, but a they all just seem to die at the point where your about to finish the job and need charging.....

 

[Ross365]

interested in trying this process, already have the vacuum pump (fridge type). Any chance you could stick up a few photos of your set up, what you use, so I can blatantly copy it and give it a go... thanks

I don't really have a "set-up"; just bits of equipment I can use for this purpose. The cleaner is in the kitchen, the oven in one corner of my garage and the rotary vac pup in another corner. This is all equipment I bought when I was running a small business some years ago. The oven in ancient and is a similar model to this https://shop.unigreenscheme.co.uk/o...nson-and-mercer-vacuum-oven-lab-heating-c4m0z.

Aspen fuel may be worth a try.

 

[MCKDAVID]

thanks for that, don't have oven, but have seen some using a pressure cooker as a vac pot, already have the refrigeration vac pump, manifold guages etc.. will see if I can't throw something together just to give it a go...
Not sure the missus will agree with an old pot disapearing, but will sneak in under the cover of darkness and liberate one... in the interests of science...

 

[AVI_8]

Wow talk about re-inventing the wheel, what’s wrong with some good old fashioned carb cleaner and a high pressure air line after stripping them down completely

 

[Ross365]

Wow talk about re-inventing the wheel, what’s wrong with some good old fashioned carb cleaner and a high pressure air line after stripping them down completely

Well, I'm not sure that life is always that easy that a squirt of aerosol does the trick. The problem I had with the present job was rust in the bottom of the bowl and you'd have to presume that some particles got washed downstream... and aerosol (organic solvent, probably with one with limited cleaning power because it has comply with modern H&S and environmental standards and that rules out the best ones) may not really deal with that. I don't think that there is much use of organic solvent in ultrasonic baths these days because people know they can now do better with water-based agents, assisted by time and temperature, unless they fool themselves by thinking they can get the quick fix off the shelf in Halfords .

 

[James1979]

Apparently in aviation they use or used to use, MEK, Methy Ethyl Ketone for removing varnish deposits, I purchased some from a popular auction site, but its very bad for your liver, i think it can be absorbed through skin so gloves and masks etc, i've used it to soak carbs in sealed container then cleaned out with brake cleaner, the carbs I had wernt particularly full of deposits so hard to tell how effective it was.

+1 for MEK.

It’s good for taking anything off anything!

I use it pre TIG welding.

 

[Morrisman]

Wow talk about re-inventing the wheel, what’s wrong with some good old fashioned carb cleaner and a high pressure air line after stripping them down completely

As the OP stated, blind holes that are plugged and are 90° to the only entry hole, nothing in an aerosol will clean them out if stuff has dried hard deep down.

I once had an Edelbrock four barrel that would not stop dripping fuel from one of the boosters. A bit of googling showed me that a tiny air hole is notorious for blocking up.

It's not a blind hole, but the only way I could get it clean was snipping a piece of .6 welding wire off and using it as a tiny drill to get the baked hard crusty stuff out. Carb cleaner never touched it, or 150psi of air. Ultrasonic may have done the job, if I'd had one.

 

[Ross365]

+1 for MEK.
It’s good for taking anything off anything!

No! It's good for taking off contamination made up of organic chemicals, including dried and hardened petrol residues. But if you have particles of something like rust or other corrosion products, it's probably not going to do much for you. It's use in workplaces is now fairly limited, and it was limited even in the 1980's, when it was considered a 'bit flammable'. I've got some in the garage and it is occasionally handy.

When Freon got banned in the 1990's, we all thought the end of the world had come, but in the decades that have passed, the water-based cleaners that have come along way and are pretty damn good in ultrasonic baths and will clean many different kinds of contaminants.

 

[bricol]

That's why I have been using my vacuum oven, as per post 6. First you have to degas the liquid by ultrasonicing it for 5 minutes before you put the carb in (in this case a small Dellorto, and a glass beaker of cleaner). Then put the carb in and swirl it around and do all I can to get as much fluid in and air out. Then I put the beaker containing the carb and cleaning solution in the vac-oven and pump the oven down. Initially nothing happens but as it gets to a better vacuum, you can see a "belch of bubbles" start as air that was still in there finally comes out. When no more is coming, let it back down to atmosphere and transfer the beaker and contents to the bath.

As mentioned earlier, if it's petrol residues you need to shift, solvent like acetone or MEK may be the way to go, but some other contaminants (especially solid particles like rust) may be best dealt with using water and a good cleaning additive. However, I do sometimes think that it can be a pretty thankless task.

You can tell when de-gassing is done, at least with industrial equipment, as the noise level drops - the tanks stop "screaming".

I'm not fully convinced you are getting the air out and fluid simply placing in a vacuum - air still won't go downhill if trapped. We never did it with industrial machines - used to submerse and revolve/tumble components.

If the carb is still in the beaker, the glass does absorb power.

Rust is going to need pure power to shift - almost vibrate it off - "cleaning" chemicals aren't going to do much. You might have good results with stuff that reacts with rust, as the ultrasonics may well assist in keeping the surface exposed so keeps working on fresh material. it certainly worked using caustic on steel dies used in aluminium extrusion ( think lamp post standards etc) - left in caustic they took daysweeks to react with the cooled aluminium in the die when a change was made, to remove enough to allow it to fall out the die. Using ultrasonics to keep agitating the surface meant it had fresh caustic on fresh metal - took hours to clear out. You had to watch the hydrogen coming off though! Twin 5000 litre tanks with some serious ultrasonic power! Might be a bit much for carb cleaning though!

 

[mangocrazy]

Rust is going to need pure power to shift - almost vibrate it off - "cleaning" chemicals aren't going to do much. You might have good results with stuff that reacts with rust, as the ultrasonics may well assist in keeping the surface exposed so keeps working on fresh material.

I've had good results using citric acid in an ultrasonic tank to remove rust. Citric is good for that anyway, but the ultrasonic gives it a real boost, as does the heat generated by the ultrasonic.

 

[Ross365]

Agreed; without removing the welch plugs, it is possible/likely that you can still have bubbles even after applying vacuum, you're just doing the best you can. The smaller lab ultrasonic cleaners are supplied with lids with holes in them to allow beakers (sized to take 600ml) to be suspended in them. While plastic beakers would not do, I understand that glass beakers do not absorb very much power.

Back in the day, I worked for a company where "precision" cleaning of aerospace parts was very important; working in "cleanrooms", we had equipment using light-scattering techniques to examine wash samples to assess residual particle-counts on cleaned components. Going a step further, we sometimes washed components, filtered the washings and then looked at what was on the filter membrane with an electron microscope. Higher cleanliness certainly incurs higher costs!

I've not yet used citric in the bath, but it definitely looks like something to try.

All that said, I think I will also try some of the Aspen fuel mentioned in post #17... or buy a mower with Li ion batteries .

 

[finyuk2005]

before i had an ultrasonic bath I used a trick i had read somewhere online,
Find an old cooking pot, fill it of lemon juice, throw the carb in, and let it simmer on the stove for a while...
It worked surprisingly well!

 

[Ross365]

Right, but lemon juice is just a source of citric acid in that role and citric (get it as a powder in Wilko) is cheaper.

 

[minimutly]

So, you're saying fill the whole bath with cleaning fluid solution and sit the carb in a basket, as opposed to placing the carb in a plastic container which is suspended in plain water? Yes, I see the logic there, the only downside is you'll be using ten times the quantity of the cleaning additive, but better to do that and have it work, than skimp and fail.

Use a heated bath, with TFR for cleaner. They come out like new.

 

[Ross365]

That's interesting. I've never been a user of TFR's for any purpose, and there seems to be many of them on the market, so it's unchartered territory for me.

 

[Sergei Slovenija]

There is such a hell of a thing as DMSO. Craftsmen fill it before changing the oil in the engine and let it run at idle. Dissolves old varnish deposits. Penetrates through gloves into the skin and drags related substances. Need gloves, like plastic PE.