Model B Carb balancing

K

Kevin in NZ

Junior Member
I have just seen a Model B carb that has been balanced for using an air cleaner, the difference with this one is all the modifications were internal and could not been seen. Unfortunately I never had time to get all the details of how it is done. Does anybody out there know how to do this modification?
 
FWIW:

I use an unmodified Model B carb with about a 5" to 6" tall K&N air filter which fits the E-bay advertised "High-Boy" filter arrangement with absolutely no problems whatsoever.

This filter safely sits up high above the carburetor air intake where no fuel can get it dangerously wet with fuel.

Too rich an air/fuel mixture problem occurs when the specific filter element is not large enough to allow enough air flow to roughly equal that of having no filter.

Hundreds of past articles on Model A filter safety, and Pro & Cons of all types.

Some even recommend no air filters ....... appears to make sense for low mileage type Model A owners who rarely get out on the highway ...... do what you feel is best.
 
I have done it a couple of different ways, the most recent, the most eligent I would say, notch the gasket to vent the float bowl to the passage behind the venturi and plug the current vent. Easy peasy...

A's Always
Dave
 
31 Vicky said:
I have done it a couple of different ways, the most recent, the most eligent I would say, notch the gasket to vent the float bowl to the passage behind the venturi and plug the current vent. Easy peasy...

A's Always
Dave
Click to expand...

Will this procedure work on Model A carbs too?
 
The procedure described by 31 Vicky vents the bowl to a location above the venturi. The correct arrangement should vent the bowl to the filter side of the choke disc. I don't see how the 31 Vicky system should help in any way.
 
Thanks Richard.

Have found information on air balancing procedures using the external tubing method - Does anyone have a how-to for the internal modification?
 
Zenith carbs built from June 1930 to end had a factory installed balance passage tube from the bowl to the air horn thus allowing efficient use of an air cleaner. The air tube is cast into the side of the lower part and is clearly visible for what it is.
 
BudP said:
Zenith carbs built from June 1930 to end had a factory installed balance passage tube from the bowl to the air horn thus allowing efficient use of an air cleaner. The air tube is cast into the side of the lower part and is clearly visible for what it is.
Click to expand...


Pictures please...

I have seen this on Combine and stationary engines but not in Zenith Model A production carbs.

That does not mean that it was never done though.


Thanks
 
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From Steve Pargeter's "Zenith Model A Carburetor Restoration Guideline," Page 4:
 

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BudP said:
From Steve Pargeter's "Zenith Model A Carburetor Restoration Guideline," Page 4:
Click to expand...

Yes this is the Combine / Stationary carb design that I referred to above that was done by Zenith after Model A production ended in 1931.

Kingston carbs and others that were installed on Combine and stationary engines used a similar vent design.
 
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Per reply no. 2, I am still averaging 20 mpg in "Stop & Go" traffic with my heavy 1930 Town Sedan with my K & N Hi-boy filter on a standard Model B Zenith carburetor with no modifications ..... 3-X plugs never foul & look new.

Have no idea of mpg with no stops while on Interstate type of traveling.

The key to good performance is filter type and large enough filter air passage size.

Anyone ever had orders to run a mile with an Army protective mask on?

Experience beats reading B. S. articles.
 
Secrets of speed mag #4 April 2009 has a couple of pages by Dave Remmer with photos on how to do this. Kevin Pm sent
 
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