Dirty carbs

[Karl321]

I'm in the middle of a carb clean and rebuild, just waiting on parts.  But I thought I'd share a pic of the dirtiest carbs I've ever seen.  (This is about my 10th set of carbs that I've rebuilt.) My heart sank when I opened these up, I thought they were a lost cause and I'd be hunting down a replacement set.  The slides, the floats and the butterflies were completely frozen, and the corrosion looked extreme.  I can't believe I didn't break off one of the float piers driving out the float pins.  But they eventually cleaned up with BP Blaster and several sonic baths, and should be just fine. We'll see!

[86FJNJ]

looks great, what fluid do you use for the ultrasonic cleaner and what temp and for how long?

[Karl321]

I buy Tillbrook Ultrasonic Cleaner on Amazon.  My machine has a 30 minute timer and heats to 175 degrees.  I usually run parts through a 30 minute cycle at around 150 degrees.  I ran these carbs through a cycle once to free everything up, and two more times after they were completely disassembled.

The first few carbs I cleaned I just used Simple Green.  It seemed to work okay.  But I switched to Tillbrook after getting a recommendation from a bike mechanic to use something specifically for ultrasonic cleaning.  He recommended Omega Clean, but I couldn't find it.  So I bought Tillbrook carb cleaner.   

[Warp84]

Simple Green is what burned the coating off my carb bodies. I'll have to see about that Tillbrook Cleaner you mention.

[Karl321]

It's $36 on Amazon for a gallon of concentrate that mixes to 8 gallons.  It says its safe for all metals, but that could just be the marketing department.

[MarioR]

Simple Green is what burned the coating off my carb bodies. I'll have to see about that Tillbrook Cleaner you mention.

10% simple Green + 10% vinegar + 15 min in 50-60 degree process = decent results but still no original effect.

Anyone tried Omega Clean solution yet? Pics?

https://www.omegasonics.com/product/omegaclean/

Thanks

[red]

Simple Green is what burned the coating off my carb bodies. I'll have to see about that Tillbrook Cleaner you mention.

10% simple Green + 10% vinegar + 15 min in 50-60 degree process = decent results but still no original effect.

MarioR,

EEK! The regular Simple Green is NOT suitable for any use with aluminum. There have been problems, described by the maker as "hydrogen embrittlement," causing cracks in the aluminum over time.
The maker now offers an "aluminum safe" version of Simple Green, but the container has a very different label. So you know, there really was a problem there.

[Troyskie]

Red is right.
Just checked the SDS for the Simple Green Pro HD, purple colour. It states the pH is 10-11.5.
Never allow pH greater than 8.5 anywhere near aluminium.

Aluminium is stable in pH ranges from about 4-8.5. Greater than 8.5 and aluminium is susceptible to alkaline attack.

Essentially the outer passive aluminium oxide layer, or anodic (anodised) aluminium oxide layer is stripped.

As aluminium is highly reactive (conductive), it tries to re-grow the oxide layer immediately, thus accelerating surface pitting.

If, as in the very warm ultrasonic cleaning environment, there is a lack of oxygen in the solution near the aluminium it becomes self sustaining (autocatalytic), a process known as hydrolysing (possibly where the maker mentions hydrogen embrittlement).

Overall, aluminium is tough, but incredibly reactive to alkaline attack. If there is any salt/chlorides/chlorines etc, and free oxygen is taken up by other processes, in a solution that has pH higher than 8.5 the cleaning solution will be very aggressive and damage the surface.

Troyskie

[MarioR]

Simple Green is what burned the coating off my carb bodies. I'll have to see about that Tillbrook Cleaner you mention.

10% simple Green + 10% vinegar + 15 min in 50-60 degree process = decent results but still no original effect.

MarioR,

EEK! The regular Simple Green is NOT suitable for any use with aluminum. There have been problems, described by the maker as "hydrogen embrittlement," causing cracks in the aluminum over time.
The maker now offers an "aluminum safe" version of Simple Green, but the container has a very different label. So you know, there really was a problem there.

Correct, aluminum safe version, not old formula.

[axiom-r]

Red is right.
Just checked the SDS for the Simple Green Pro HD, purple colour. It states the pH is 10-11.5.
Never allow pH greater than 8.5 anywhere near aluminium.

Aluminium is stable in pH ranges from about 4-8.5. Greater than 8.5 and aluminium is susceptible to alkaline attack.

Essentially the outer passive aluminium oxide layer, or anodic (anodised) aluminium oxide layer is stripped.

As aluminium is highly reactive (conductive), it tries to re-grow the oxide layer immediately, thus accelerating surface pitting.

If, as in the very warm ultrasonic cleaning environment, there is a lack of oxygen in the solution near the aluminium it becomes self sustaining (autocatalytic), a process known as hydrolysing (possibly where the maker mentions hydrogen embrittlement).

Overall, aluminium is tough, but incredibly reactive to alkaline attack. If there is any salt/chlorides/chlorines etc, and free oxygen is taken up by other processes, in a solution that has pH higher than 8.5 the cleaning solution will be very aggressive and damage the surface.

Troyskie

Troyskie - Once this process has started can it be terminated? If so, how? I have some rare old two-stroke carbs that are definitely trying to regrow the oxide layer...  I tired a baking soda bath and I keep them wet with WD40 to abate the process but when they dry it begins again. There is no significant pitting or damage that is concerning (yet) but they sure won't clean up for use.  Are they garbage now?  What do you do??

[Troyskie]

Troyskie - Once this process has started can it be terminated? If so, how? I have some rare old two-stroke carbs that are definitely trying to regrow the oxide layer...  I tired a baking soda bath and I keep them wet with WD40 to abate the process but when they dry it begins again. There is no significant pitting or damage that is concerning (yet) but they sure won't clean up for use.  Are they garbage now?  What do you do??

G'day mate, the hydrolysing or alkaline attack, ends immediately once oxygen is introduced, i.e. some fresh water.

I wouldn't use baking soda as that itself is pretty alkaline, 8+ google just told me.

I just checked the SDS of WD40, it has a pH of 9.5 - 11.5, so steer clear of that.

I don't think the casting is anodised, so it only has a thin passive layer.
Aluminium grows about a 7 micron thick passive layer pretty quickly when exposed to air/oxygen.

A fix could be ultrasonic cleaning with just water (and possibly a few drops of hydrogen peroxide) to prep the surface of these carbies and stop any white powder (excess aluminium oxide) forming. I'd use distilled water if your tap water is 'hard' as that is pretty alkaline as well.
If you want to give them a light coating afterwards, I'd suggest a light mineral oil as this doesn't have any water and thus has no pH.

If I was to do the same thing I'd do the distilled water + hydrogen peroxide in the u/s cleaner, then blow them out and coat with mineral oil (I prefer the Singer mineral oil brand), and then blow them out again to force the mineral oil into the crevices but leave only a very thin layer that can be removed later with the u/s cleaner when you're ready to service/use them.
An alternative oil I use for long storage is Lanox, not sure if you have it in the US, it is a lanolin based spray wax I use on some old muzzle loaders that rarely get used. This stuff is easily removed and very long lasting. I think the longest they were stored was about 40-50 years and they came out good as new once cleaned.

From memory there have been comments about hydrogen peroxide and u/s cleaners, so I might be wrong about this bit.

Troyskie

[axiom-r]

Thank you for the tips and advice!  I will investigate Hydrogen Peroxide and ultra sonic cleaners and try to locate a proper mineral oil like lanox.