No more stalls at stop signs for me!

[pgerhardt]

I installed my new manifolds with a professionally rebuilt Zenith (flow tested jets and tested on the rebuilder's car), and my tudor ran great (picture 1) with good acceleration and a nice idle - but! . . . It stalled after moderate stops.

I did my research and discovered that this is a common problem with Zeniths that may be solved with adjustments to the float. Rather than fool around wth the Zenith's float level I did more research and found that the Marvel-Schebler carburetor was highly recommended, did not suffer from stop-stall, and was used in the 1930's by model A owners with Model B/V-8 envy.

So by the power of E-bay I got a fully rebuilt Marvel-Schebler and put it on today (picture 2). My tudor retained all the benefits of the well rebuild Zenith, but without any of the stop-stall problems. Yea! The Zenith is now my spare carb.

[Marshall V. Daut]

It's great that you have solved your stalling problem at stop signs and can enjoy driving your Model A, but 5,000,000 Model A's came from the factory with Zeniths that did not stall at stop signs. The problem with your Zenith undoubtedly lies in the Zenith. SOMETHING was not restored or adjusted properly. Try lowering your float level a little bit, as the late master Zenith rebuilder Rex Reheis recommended to stop stalling conditions. Too often Zeniths get a bad rap because they were not completely and properly rebuilt. Close, but no cigar. A well-rebuilt Zenith will not stall upon sudden stops. Don't give up on your Zenith quite yet. They are great carburetors when someone takes the time to completely cleanout and rebuild them with the correct jets and parts, which yours apparently has. Assuming all the passageways were cleaned out - and not just by soaking in cleaner and blowing out with compressed air - my guess is the float level is incorrectly adjusted. Play with that before throwing the baby out with the bathwater.
Marshall

[Mitch//pa]

what Marshall mentioned plus i like to have the correct looking parts on my car. your zenith just needs a little tweaking most likely you just have to add a washer under the needle valve seat to lower the float level, a 5 minute fix....dont give up on it. your engine bay looks much nicer with the zenith...

[C26Pinelake]

I think you could have had the Zenith properly adjusted much cheaper than buying a rebuilt Marvel. I would have returned the Zenith to the professional rebuilder! Wayne

[pgerhardt]

Don't worry I am not going to get rid of my Zenith. but for now I am just going to enjoy driving my A without the fear of angry traffic piling up behind me at a stop sign. When everything else that needs doing is finished on my tudor, I'll revisit the Zenith and see if I can adjust the float to eliminate the stalling problem. If I am successful then the Marvel-Schebler may become my spare carburetor.

[George Miller]

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[C26Pinelake]

Originally Posted by pgerhardt

Don't worry I am not going to get rid of my Zenith. but for now I am just going to enjoy driving my A without the fear of angry traffic piling up behind me at a stop sign. When everything else that needs doing is finished on my tudor, I'll revisit the Zenith and see if I can adjust the float to eliminate the stalling problem. If I am successful then the Marvel-Schebler may become my spare carburetor.

Why not return it to the professional rebuilder. They normally bench text them! Wayne

[MikeK]

I'm all for originality, but the Zenith carb design did change for 1932. The float pivot axis was turned 90 degrees and the carb was redesigned to resist the known effects of deceleration on fuel level.

[C26Pinelake]

Originally Posted by MikeK

I'm all for originality, but the Zenith carb design did change for 1932. The float pivot axis was turned 90 degrees and the carb was redesigned to resist the known effects of deceleration on fuel level.

But bottom line it remains a Zenith! Wayne

[P.S.]

The rebuilt Zenith carburetors I bought from Bert's don't have an issue with stalling at stops.

[C26Pinelake]

I buy mine from Bill Buckmeyer and they are without a flaw amd all tested on a Model A. I could not be happier !
Wayne

[Al 29Tudor]

I had the same stalling years ago but fixed it by adding another washer under the float valve. It's perfect now.
Also fixed a friends Zenith the same way.
Al

[afuncar]

I had a problem with stalling at stops when I searched the problem I found the gas linkage was slightly bent causing idle on high speed circuit. Bent linkage so throttle closed and engine idled on idle circuit solved problem.

[1930artdeco]

Mine will stall if I don't have the GAV open about 1/4 of a turn in around town traffic. On the freeway I turn it down to about 1/8 or so.

Mike

p.s. How do you like you like your Marvel? I have one that I am going to tune up and try out on my car for the fun of it. I would like to make a good comparison between the two.

[H. L. Chauvin]

Appears one's common sense carburetor decision and choice is always .......... never to use a vintage "round" bowl Zenith "presently" causing flooding ........ seems far better than possibly experiencing whiplash, flying through the windshield, and/or a crushed metal Model A rear end.

One helpful proper and correct fix is described in the book: "Restoring The Model A and B Carburetors The Rex Reheis Way" where one can maintain a regular low engine idle at stops.

It recommends changing and lowering Ford's recommended fuel level of 5/8".

For example, it recommends lowering fuel level an additional 5/16", i.e., 15/16" measurement as opposed to 5/8".

Also recommended is using the preferable "Renner's" fuel level gauge which is larger & far more accurate to within 0.10" as opposed to the cheap and smaller fuel level gauge which "always" gives less accurate readings with its smaller clear plastic tube with the pronounced meniscus display on the top of the column of fuel.

Hope this helps.

[BILL WILLIAMSON]

If you just "HAPPEN" to get your float level "JUST" right, you "MAY" solve your stalling problems??--BUT, remember, the Zenith is an old SLOSHY design & REALLY good brakes & REALLY good tire grip, complicates the problem.
I'll try Vermin with the existing carb that "somebody"?? else built, but I have a PRIMO Tillotson, just in case. It has been loaned to a friend & run for 6 months, flawlessly!
Bill W.
Bill W.

[mshmodela]

I suppose rebuilding a carburetor is like most anything... a bit of learning curve... Great news your new carb and manifolds have fixed your problem... Now spin the wheels and enjoy

[BILL WILLIAMSON]

Originally Posted by mshmodela

I suppose rebuilding a carburetor is like most anything is a bit of learning curve... Great news your new carb and manifolds have fixed your problem... Now spin the wheels and enjoy

I "accidentally" laid 10" of tire marks on the driveway. Gregg, (RIP) coated them with 3 coats of Epoxy Resin, & they're still THERE!
Bill W.

[H. L. Chauvin]

Something never mentioned is that gasoline has about 25% less buoyancy and upward force as that of water.

Float weight, with or without solder repairs, and floats with or without unseen solder inside a float repair may be a float weight factor affecting float height in gasoline.

Could some replacement floats weigh more than others?

What about old floats dented inwards on the bottoms of floats?

Are all floats the same?

An accurate fuel level gage may help to "see" if there is any difference in float height.

[Charlville]

If it makes you enjoy your car and encourages you to drive it more, it's the right thing to do IMHO