Carburetor disassembly tip

[carbking]

Disassembly of screw-in parts on cast iron carburetors

 

Remove everything that heat can hurt (venturi, springs, etc.); put the casting in an electric toaster over, and heat as hot as you can get it. Now remove, and spot heat the CASTING where the jets thread in (not the jets, just the casting) with an acetylene torch until these areas of the casting are cherry-red. Place the casting back into the toaster oven at maximum heat, leave for about 5 minutes, then turn off the oven, and allow the casting to cool (DO NOT QUENCH).

 

Remove the cool casting. Often, you can now remove the jet with your thumb-nail.

 

DO NOT USE THE HEAT TECHNIQUE ON POT METAL!

 

For pot metal carburetors

 

Cleaning via either an ultrasonic cleaner, or boiling in water and soap is permissible. Do NOT blast prior to complete assembly.

 

A zip-lock bag and freeze overnight in your freezer, then apply the spray freeze to the jet. This may need to be repeated, occasionally several times

 

Make a special screwdriver from a piece of steel bar. Measure the thickness of the slot in the jet(s) to be removed. Now, mill from the end of the bar, leaving a ridge 0.005 thinner than the thickness of the slot, and as tall as the depth of the slot less 0.005 inch.

 

The flat end of the bar can now rest of the top of the jet, with the ridge inserted into the slot. One can now use pressure against the top of the jet, and rotate. Now possible to use more rotational pressure without the ridge slipping out of, and destroying, the slot.

 

For those disassembling (or assembling) carburetors with a power valve (a.k.a. economizer valve) with a spring-loaded plunger in the center of the valve (many Strombergs, many Rochester), machine a hole in the center of the end of the bar with a diameter larger the the diameter of the plunger before milling the end of the bar. This will prevent the valve from internal damage caused by a straight-blade screwdriver.

 

Someone once said a picture is worth a thousand words.

 

Look at this link, and scroll down to the T109-61 to see a factory tool as described above.

 

https://www.thecarburetorshop.com/Carter_tools.htm

 

Jon

[Walt G]

THANK YOU Jon, excellent advice that is most appreciated.

[carbking]

Walt - the heating/cooling technique is one of the lessons in the "Metals" curricula of the "School of Hard Knocks".

 

The description of how to make the tool is merely an observation of a solution designed by a carburetor engineer, and re-described such that those without access to the special tool may have one.

 

Jon.

Edited April 8, 2022 by carbking (see edit history)

[Walt G]

Jon - The fact that you took the time to explain what and how to do it serves all of us, either immediately or perhaps years from now.

that is what preservation is all about. First and foremost.

For decades I have been involved in seeking out and preserving information, photographs, etc of the past - be it local , state or automotive history, how things were done and perceived, who did this, as mentioned "first person" experience. Some people want that information for themselves and let others know they have it but do not share because it makes them more important that others DO NOT know. Not my mindset at all. One can't help everyone all the time but when you can.............why not? I have the utmost respect for people who are skilled in a topic/subject that I am not and for them to let the rest of us know in a way we can understand it is priceless. You have done that for all of us, but most will not take the time to say thank you .

Walt

[Mark Wetherbee]

I took Jon’s advice of the ultrasonic cleaning for the Stromburg UU2 in my Pierce and it took a couple rounds in his ultra top secret solution (Dawn ultra that is) and it was apart with absolutely no issues. Every port plug, screw and jet came out and the interior ports were easy to clean using a torch tip cleaner.
 

I don’t know if I would have had the nerves to use heat but after the success I had with Jon’s advice I would have done it had the cleaner not done the trick as well…

 

Thank you again for your taking the time to post such a detailed sequence for these fragile carburetors.

[Pfeil]

The application of cold and heat can make all the difference. I was taught this in 7th grade metal shop and use that information to this day. Last week I did a valve job. While installing valve guides, the heads were in the oven to 600 degrees and the silicone bronze valve guides were in the freezer. Take the head out of the oven and the guides out of the freezer and the guides can be pushed in with a finger. That lesson that was learned when every boy/teenager in school had to take metal, electric, wood, print, shops and drafting from the 7th to 9th grade. 

[bradsan]

I think the tip translates to if  you are reaching for the box wrench to add to the flathead screwdriver you are using on the carb think again..and then think again.....and if you still have the box wrench in your hand hit yourself on the head with it because it will still be cheaper than getting someone to fix the problem you are about to create..

I was fortunate that Mark was still rebuilding carbs when I had to send him my 'problem'. The number of people with the skills, abilities and, most importantly, inclination to manufacture small parts is dwindling rapidly

 

Heat is good until you have a fine thread fastener then the situation can become quite galling!

 

Great tip. Especially the patience to let things cool down

[intimeold]

Great advice.

 

Too many carburetors were ruined by improper disassembly.

 

intimeold

[31plymouth]

So what is the best way to release a stuck accelerator pump on a carter BB1? 1932 Plymouth

[carbking]

12 hours ago, 31plymouth said:

So what is the best way to release a stuck accelerator pump on a carter BB1? 1932 Plymouth

Exact same technique IF someone has not pulled out the pump shaft; except heat the pump well (assuming you have the CORRECT cast iron BB-1).

 

Once you have done the heat, fill the pump cylinder to just cover the plunger with your flavor of penetrating oil (personally, I detest them all, as they all stink!).

 

Let the lower casting set for a few hours; then use a brass drift punch and a hammer, and GENTLY try to drive the plunger further in, allowing more coverage of the oil. Now pull the plunger out. You may have to work it back and forth.

 

DO NOT USE ON THE LATER ZINC ALLOY BB-1 CARBURETORS.

 

In more than 50 years, have never had this technique fail on a cast iron BB-1.

 

But if the lack of patience gets in the way, the plunger and rod are available.  

 

Jon

[31plymouth]

14 minutes ago, carbking said:

 

16 minutes ago, carbking said:

DO NOT USE ON THE LATER ZINC ALLOY BB-1 CARBURETORS.

 

In more than 50 years, have never had this technique fail on a cast iron BB-1.

 

But if the lack of patience gets in the way, the plunger and rod are available

 

Thanks for your reply

It is a cast iron BB-1.  i will try this method and will be buying a new rod and plunger for sure.

[carbking]

If you (or a previous owner) has not yet destroyed the rod and plunger, no need to buy one; it will come out undamaged.

 

Jon.

[wayne sheldon]

Wonderful advice and suggestions! Very well written!

I am going to bookmark this thread.