MTFCA Forum

How do I get the black cone out? I removed the wire keeper, but cone is sure stuck.

A carriage bolt of the right size can be used to pry the venturi out of the carburetor body. As Steve notes, the part may break easily; they are "pot metal" and subject to decay with age. I've seen some that were solid and sound, but more that were too decayed to be useful. Fortunately new aluminum ones are available.

Chances are it has swollen with age and will get broken when trying to remove. It's not black it's dirty, they were a pot metal and would have been about the color of dark aluminum. Heat will just melt it. You could try good penetrating oil, not WD40. Seems to me someone was just looking for one because they are out of stock.

The MTFCA Carburetor book (which would be a good investment at this point) says to use a long 5/16" carriage bolt. Slip the edge of the bolt head under the venturi and use it to pry it up. Use lots of good penetrant (50:50 ATF and Acetone) for a day or two to loosen it, then pry it out using the carriage bolt.

Mark Gregush wrote: ↑

Sat Sep 26, 2020 10:15 pm

Chances are it has swollen with age . . .

Exactly, Mark. I've found that characteristic "swelling" is an indication of decay. Don't be upset if you break it trying to disassemble. The "sound" ones I have found came apart fairly easily.

Thanks Guys, had to dig it out. Made a couple of tools to finish getting it apart and all went well after the tube.

It came out in one piece? Cool. This G venturi was easier but it was in pieces.
Any cracking found yet?
From a part of the model railroad world on preserving pot metal/white metal and even Zamac frames/bodies:
One fellow used heat (low oven) to drive out moisture then saturated the cracks with CA (super glue) to help hold it together longer.
I have some Riva-Rossi steam engine frames I'm watching long term.
Not bad yet along with oil immersed Farmall tractor oil pump pressure valve assy's made of the same material.
One crumbled, another soon to crumble. The one that went into the tractor is only a matter of time.
Wondering: Good acetone will dissolve super glues so I don't know how gasoline will react to it.
Sorry about the babble but it's on my mind on all fronts also.

After reading the writings of Herbert Franklin (Franklin automobiles, who got his start by perfecting the die-casting process, which gave him the money to start building automobiles) the explanation is fairly simple. Die cast parts are made with zinc. The more zinc in the mix, the easier the part is to cast in a mold. So you can make up for poor molding practice or bad tooling, or poor heat control, by adding more zinc to the die-casting mix.
The problem with zinc is that it NEVER stops changing. It swells with age and changes in temperature and humidity.
The die-castings on my Franklin are perfect in every way, after 94 years. H.H. Franklin knew his die-casting, and he used very little zinc, and kept tight control over his molds, temps, and everything else. The result is very solid and stable die-castings.
On the other hand, I have just taken a Model T AC speedometer apart, (From a 1927 Coupe, that had 30,000 miles on it, and looked like new) and the die-cast support that carried all the gears and drums was bent like a banana. It was obviously a very cheap die-casting. I was told by Russ Furstnow, that AC speedometers were the cheapest Ford could get, and also the worst in quality. They had a very high failure rate, and there was no provision for repairing them or overhauling. They would be thrown away when they broke or jammed. I am looking at putting a Stewart-Warner in to replace it.
The Holley G on my 1914 had a cheap pot-metal or die-cast venturi, and it fractured into pieces when I went to remove it. The new aluminum ones are much better, fit perfectly, and won't swell or deteriorate like the originals. Even if you got your venturi out in one piece, I would throw it away and put in a new aluminum one. They aren't worth messing with more than once.