Model B carburetor

old31 said:
So purdy, when you say "slightly lowering the level of the float has solved the problem".

Would you set it for 6/8 or 7/8 below the seam instead of 5/8?
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When I slightly lower the float to solve stalling problems , I don't measure , I only very slightly lower the float . I very seldom have to go back and readjust the float after slightly lowering it . If the float is too too low it will cause power loss and backfiring caused by too lean operation . It is more less just a feel that can be developed or in some cases , trial and error .
 
daren007 said:
I have had two B carbs and neither had the baffles. I have not had stalling problems with either one. Did the B carbs leave the factory with baffles or is this a aftermarket thing.
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There were a few variations in some of the B carbs . The earlier ones didn't have baffles . Some B carbs had a smaller venturi if they were sold as a replacement for the Zenith one or two carbs used on the model A . Some had round floats while others used a rectangular float . Ford usually made minor changes as time went on in an effort to improve operation .
 
Chuck Sea/Tac said:
I was under the impression the baffles had to do with inlet fuel pressure.?
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There was a spring used with the model B float to help with fuel pressure caused by the fuel pump used on the B engines . When I use B carbs on the model A , I always remove the float spring .
 
Brian T said:
Hi Purdy,
From what I remember reading they are used if you have a mechanic fuel pump, they deflect the pressure pulses away from the float, I suppose without it, it could cause the float to lift of the needle and seat.

Regards Brian.
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Hello Brian , Not tring to be a smart azz but I think that the float spring was for that purpose .

Best regards , your friend Purdy .
 
daren007 said:
I don't think the baffles would apply to the B carb as the float hinges north-south vs east-west.
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Probably most of the model B carburetors came from the factory with baffles . Some had one baffle and the best that I remember , some had two baffles . I've never heard of a baffle that was offered as a replacement part , they were cast in place in the lower carburetor housing .
 
I think that they might be referring to 9652 , the brass baffle that fastens to Float hanger on SOME B Carbs..


UPDATE:


Looked at Bratton baffle ... it is in fact the p/n 9652.
 
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Lots of folklore and myths in the above thread!!!

All 1932 through 1948 Ford model B Zenith carburetors left the factory with the fuel level set at 5/8" below the gasket line and all of them operated perfectly!

The only way to accurately set the float is with an external sight gauge that shows the actual working fuel level inside the float bowl.
The level should be adjusted by raising and lowering the float valve needle and seat using different thickness gaskets, Never by bending the float tab.

There were 2 versions of the Ford model B Zenith carburetor.

The Zeniths produced from 1932 to 1934 are known as the B-1
It had a base drum shaped float, apparently this worked well but could possibly displace too much fuel in the float bowl under certain conditions.

The Zeniths produced from 1935 to 1948 are known as the B-2
They had a smaller rectangular float with a baffle to limit fuel sloshing, the float and baffle operate independently from each other. There was also a very light spring in this assembly to aid the float in shutting off fuel pump pressure.

Other than a design change, turning the float 90° from the Ford model A Zenith design had nothing to do with stalling when stopping.

They made 5 million Model A's none of them stalled when coming to stops when they left the factory.
It would not have taken them 4 years to address a problem like that, it would've been immediately resolved.

So if turning the float 90° stopped stalling when stopping, why didn't the cars start stalling when they turned hard right or left?
 

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Dave, on the bracket that hangs your carb, is it level or do you set it at an angle of 3.5 degrees.

Or doesn't it matter?
 
All nonsense!!!

Ford never had troubles with stalling at stops with any A or B released carburetor with the fuel level at 5/8" below the gasket line using an external sight tube to check/set the fuel level. They never would've sold a single car if this was an issue. There would've been all kinds of service bulletins released to the dealers to warn of and fix this problem.
 
My test stand has a carburetor setting level.... 3-1/2° Doesn't matter, set the level on or off the car... we're measuring fuel level 5/8" below the gasket line with a ruler how accurate could we be anyway? Always error towards less fuel in the bowl than too much. We don't want it to overflow out the jets when it's parked. It's next to impossible to starve the carburetor as the fuel inlet valve provides almost twice as much fuel as all the Jets combined use at wide-open throttle.
 
ursus said:
I have found the best setting to be where the seam joining the upper/lower halves of the float is parallel with the casting edge.
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A spec is just a spec...in many cases just a starting place. I've found the B carb needs a little "experimentation" when on an A. After a bunch of tries, my float is set at a slight upward angle when needle is closed. Works for me. I dare anyone to set a 54 ford carb at the 1/64" level of accuracy that the gauge in the repair kit measures.
 
My B carb has no spring, no baffle, and a rectangular copper float.

FYI, I set the fuel level with the car running.
 
I have a B carb on my A, square float and replaced the missing brass baffle. I purchased the level gauge from Renners and have it set exactly as the picture above. It took 2 tries because I found out close is not good enough.
 
rich40701 said:
I have a B carb on my A, square float and replaced the missing brass baffle. I purchased the level gauge from Renners and have it set exactly as the picture above. It took 2 tries because I found out close is not good enough.
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Sometimes it takes a couple tries.

Always best to error towards less fuel in the bowl, too much fuel overflows out the jetting.

The fuel inlet valve lets in twice as much fuel as the Jets can use.... running a float bowl empty is next to impossible!
 
Dave,


With respect, the new design B carburetor float and baffle assembly was a change in the 1934 model year. Service Letter #8 from Dearborn to the dealers, dated May 17, 1934, announced that the changes had been released for service and production.
 
jsulliva said:
Ford DID have a problem with the Zenith Carburetors on the Model A stalling when stopping, which is why a small passage in the top section (lid) from above the float bowl area to the secondary well was added. See last symptom here:
https://modela.org/engine_dies_stop.html and last paragraph "It was found ..." and the picture here: https://modela.org/upper_passages.html
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HI

This carburetor website you reference modela.org owned by Berts Model A Parts was put together by Chris Pelikan is not directly Ford documentation, some of it is assumptions made by the author.

I don't see the connection of the "Upper Casting Passages" page talking about the float bowl vent holes TO the "Engine dies when vehicle comes to a stop" page.

On the "Upper Casting Passages" page the note about the added vent hole is because Zenith wanted to be sure the bowl was venting properly to prevent the bowl area from becoming air locked, like not opening the vent on a gas can.
It makes no mention of a improper vented carburetor being the cause of stalling at stops.
This would not cause a stall at stop, this simply would cause the engine to run out of fuel, this could happen at any speed.

The whole page "Engine dies when vehicle comes to a stop" is very poorly written....
If the float is set too high it would be overflowing out the main jet and be leaking on the ground even before the engine was running.
"The idle adjustment screw is mis-adjusted?" How? Rpm too low?
"Upper casting idle jet passage is restricted to idle throat port?" This has nothing to do with the float bowl vent mentioned in the "Upper Casting Passages" section. This is talking about the Idle Jet to Idle Aperture passage.

Nowhere ever have I seen Ford or Zenith documentation addressing stalling at stops or the like.

Anyway, I'm not trying to be mean or be harsh.
I'm just trying to understand the links you referenced and possible learn more from other resources.
Hopefully I haven't misinterpreted.

Have a great new year.:)
 
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