Tanking carbs

[Anticept]

EDIT: WARNING:

 

See the bottom of this post before using an ultrasonic cleaner.

 

 

 

So I picked up an ultrasonic cleaner that was discounted on amazon (I don't like to go cheap on tools, but I don't mind deals!). Decided I would tank a couple 2000+ hour carbs to see what comes out.

First dip, low frequency, 30 minutes, 160 degrees:




Second dip, high frequency, 30 minutes, fresh cleaner, 140 degrees:



Second dip with fresh cleaner and you still can't hardly see it after it's done!


Pulling it out after the second dip:



Pretty clean, but some of the cleaning deposited the dirt elsewhere. I need to do a couple more dips in fresh cleaner again! I'll probably do 10 minute jobs from now on though, it didn't take long for these things to dirty the water fiercely.

Why didn't I disassemble the carb first? I'm going to overhaul them, replacing almost every moving part, needle, o-ring, and valve. But first, I wanted to see just how deep this cleaner can get; I wanted to see if it is just pulling dirt on the outside of the carb off, or if it's actually loosening up dirt in the passages.

By the way, anyone know what sealant rotax uses to cover over some of the machining plugs used in manufacturing? They are almost like little tiny rivet heads. You can see two of them in my third picture to the right of the mixture screw, recessed into the body. The cleaner took that sealant off, and I am not sure what kind it was.

Just a small warning, by the way. This cleaner (or maybe the solvent) also seems to have destroyed a couple of the o-rings, I found bits floating around from both carbs. Again, I'm overhauling, so I'm not worried, just a fair warning. In fact, it's probably a really bad idea to leave carbs assembled like this if you plan on using them as-is again.

 

EDIT: WARNING:

 

11/2/14

 

Hi All!

 

I forgot to get back on this thread.

 

The ultrasonic cleaner that I used did a little bit more than just cleaned. It's such an incredibly powerful transducer, that it removed the brown coating on carb throat (I had top side down in it) when I had tanked it for an hour (in retrospect, this was WAY longer than what was needed). I also tanked a bunch of little parts at once after the carb body, and now I have realized I should have only put in like metal with like metal. I was trying to remove the fuel varnish, which takes a little longer to work off, but I also put in the aluminium parts. Aluminium is soft and the long tanking put mild microscopic pits on the piston (as well as the throat of the carburetor), enough to cause the piston to be a little sticky with a side load applied. I will likely need to lightly polish the piston and the throat of the carb for smooth operation again. If a scotchbrite pad isn't enough, I will end up having to order new carbs as I don't want to change the clearances...

 

I kinda figured that the brown stuff floating around was largely the coating on the carb (it's not a critical coating as I have been told by rotax support) as well, that wasn't all dirt.

 

I'm used to cheap-o cleaners and this is the first time I sprung for an industrial grade ultrasonic cleaner. BIG difference. One of those "learned the hard way" things.

[Anticept]

Aldo, i feel i should add this:

 

I got a synchromate a few days ago and moved away from gauges. The accuracy is extremely high, plus there's an unexpected feature. I can watch how the carbs stay in balance much more easily as I shift throttle. On one of our CTs, at low throttle, one of the carbs is dragging a little at low RPM as you increase throttle, but if you pull back on the throttle, they stay in sync. It only happens at low RPM (idling range), and stops once you start running any appreciable throttle setting. The other CT, which has brand new carbs on, does not do this.

 

I noticed after tanking the first carb, that the throttle has a noticeably smother swinging action vs the one I still had to tank. After tanking the second one, they both have a very smooth action. I suspect that the carb that is dragging is a bit dirty too, so once i have overhauled my extra set, I will put them on and tank the other set.

[Jim Meade]

What are you doing up at 0400 in the morning? Guilty conscience?

What size is your ultrasonic cleaner?

As a general question to all, what size would handle most light mechanic jobs? 1/2 gallon? More? Less?

I see Grainger has many for sale in the $500 and up range. Didn't look at Amazon.

[Roger Lee]

Hi Correy,

 

When using a sonic cleaner or carb dip you may have to re-epoxy / seal the small ball-bearings on the outside which are plugs from the carb Mfg. These products tend to strip, loosen and or cause these ares to leak. If you use the sonic cleaner I would include the application of the epoxy as a standard practice.

 

I have tried the carbmate and syncromate. They can spit a hair, but can not diagnose a carb problem and you don't know which carb to work on or why. The diagnostic drawl back is huge for me and would have cost hundreds of more hours of work. The hair splitting part is gone once you hook the carbs back up. My carb syncs usually just take minutes to do if they are adjustable because just a glance at the gauges tells me volumes and exactly what I need to do.

With gauges I can tell immediately if cable length  needs to be adjusted on the throttle arm attachment, which carb I need to adjust and whether there is enough adjustment left to accomplish the task, how far each carb is out from each other and which carb to go after, I can tell you if the carb has a clog in the idle or main fuel circuit, I can tell which carb is controlling the idle verse the other, ect...

The electronic devices can do none of that with just a glance of the display.

 

I think in this case the simple analog gauges wins out over the electronic one.

 

Put a set of gauges inline with the carbmate and you'ed have a carb sync device on steroids.

[Doug G.]

Hmm...never thought of using both. Sounds like a good idea.

[Anticept]

What are you doing up at 0400 in the morning? Guilty conscience?What size is your ultrasonic cleaner?As a general question to all, what size would handle most light mechanic jobs? 1/2 gallon? More? Less?I see Grainger has many for sale in the $500 and up range. Didn't look at Amazon.

 

Just having fun playing with toys. I love to work on my plane as much as fly her. I'm a lot like those motorheads that work on cars, always looking for ways to improve.

 

Cleaner is 2.5L (approx half gallon). it's a decent size, and i got it for dunking carbs in addition to small parts. The important part is the heater. Ultrasonic causes cavitation, which is what is loosening the dirt. It works best around 160 degrees.

 

Hi Correy,

 

When using a sonic cleaner or carb dip you may have to re-epoxy / seal the small ball-bearings on the outside which are plugs from the carb Mfg. These products tend to strip, loosen and or cause these ares to leak. If you use the sonic cleaner I would include the application of the epoxy as a standard practice.

 

I have tried the carbmate and syncromate. They can spit a hair, but can not diagnose a carb problem and you don't know which carb to work on or why. The diagnostic drawl back is huge for me and would have cost hundreds of more hours of work. The hair splitting part is gone once you hook the carbs back up. My carb syncs usually just take minutes to do if they are adjustable because just a glance at the gauges tells me volumes and exactly what I need to do.

With gauges I can tell immediately if cable length needs to be adjusted on the throttle arm attachment, which carb I need to adjust and whether there is enough adjustment left to accomplish the task, how far each carb is out from each other and which carb to go after, I can tell you if the carb has a clog in the idle or main fuel circuit, I can tell which carb is controlling the idle verse the other, ect...

The electronic devices can do none of that with just a glance of the display.

 

I think in this case the simple analog gauges wins out over the electronic one.

 

Put a set of gauges inline with the carbmate and you'ed have a carb sync device on steroids.

Roger,

 

The syncmate has gauges. If you look at the top of the LEDs, it has comparison scale in cm.hg. It is comparing the right carb to the left one, so, for example, if you see the LED on the right side ("+" side) of Pa, it means that the right side induction is seeing a higher relative pressure by "X" amount cm.hg. If you further need absolute readings, the syncmate can be switched over to absolute mode and take readings on the left tube. Thats why i got it instead of just the carbmate.

 

I know that I should be careful with over-interpreting the readings when using extremely accurate equipment. However, i get quite a significant skew during acceleration near idle speeds, which the other CT is no where near as much. If, after tanking and overhauling, it still having that issue, I will do acouple other examinations as according to the heavy MM and check the throttle cable for wear, then just call it a day.

 

It's my own plane, and I like this stuff so I don't mind. It's how I learn. If it was a customers' plane, i wouldn't be charging for this as I am just following random leads to learn and discover .

 

What epoxy do you recommend?

[Anticept]

Oh, here's the cleaner too. http://www.amazon.com/gp/product/B00BSGEAJC/ref=oh_aui_detailpage_o04_s00?ie=UTF8&psc=1

 

Keep in mind, at the time i bought it, it was less than 140 on sale. If you come back to this and see it at 300, shop around. It should be found at less than 200.

 

Also, make sure you know, there are multiple types of the same model. You want the SE-GL series (or, more preferably, GL2 for extra large tank and settings memory), which is the one i linked. The important part is it should be SE-GL (or GL2), as it is the one with the full array of settings, including an important dual frequency setting. Low frequency is for breaking up thick grime, while high frequency is for loosening up finer stuff.

[Roger Lee]

If after using your cleaner yo have rough running or a hard time syncing re-seal the ball bearing plugs.

[Anticept]

If after using your cleaner yo have rough running or a hard time syncing re-seal the ball bearing plugs.

I am going to do that anyways, I just need to know if there is preferred sealant

[Roger Lee]

it's just epoxy

[FlyRatz]

Hi guys,

 

if you are sealing the ball bearing plugs, dont forget to seal the holes for the floater guidance pins in the carb bowl as well. I just had a case, where one guidance pin got loose and due to this the bowl became leaky.  From now on, I seal the holes from the outside with epoxy. (They are not blind holes)

 

 

Best greetings from sunny Stuttgart

 

Markus

[Anticept]

Hi All!

 

I forgot to get back on this thread. See my edit to my first post.

[GlennM]

Hi guys,

 

if you are sealing the ball bearing plugs, dont forget to seal the holes for the floater guidance pins in the carb bowl as well. I just had a case, where one guidance pin got loose and due to this the bowl became leaky.  From now on, I seal the holes from the outside with epoxy. (They are not blind holes)

 

 

Best greetings from sunny Stuttgart

 

Markus

I just had the same problem with one of my carbs, less than 20 hours after the 200hour inspection.