Carb: Will only start with choke even when warm

[bikemaniac]

Hi,

This winter I rebuilt the carb incl measuring the jets. I think I did a fairly good job. Now, the car starts easily with one quick pull on the choke rod, but when the engine is warm and shut off for lets say 1 minute it is not possible to start the engine anymore WITHOUT the choke. I always have to make a quick pull and then she fires up beautifully. Does anybody know how to solve that problem ... or do some carbs just need at quick pull at the choke rod at all times?

Lucas

[Patrick L.]

Mine is similar and has been so for the 40 years I've had it. Different carburetors make no difference. Doesn't bother me, haven't worn out my elbow or any linkage yet. My problem I believe is inside the engine, nothing to do with what is hung on the outside of it.

[Jon]

The choke restricts air, so maybe you have a manifold leak?

[Bruce Lancaster]

There is no way to move gasoline from the carb bowl to the intake in a Model A except the pull created by engine vacuum and venturi pressure drop, assuming reasonable fuel level in bowl. Cranking speed is probably way too low to provide airflow to get venturis pulling, and vac may be low too. You don't have an accelerator pump to give it a forced shot of gas when you step on the pedal. If the engine can't pull in gas to light it up at cranking speed, a quick application of choke will create high vac and pull some gas in to light the engine.
The choke, spring loaded to open, seems made for this...unlike later carbureted Fords, it is not meant to stay shut for a while during warmup as cold enrichment is handled by the GAV.
Lack of immediate flow in warm startup without choke could be from weak engine pull, perhaps need for a valve job, or it could be that your fuel level is set a bit low and only responds to the stronger pull from choking. Ford start instructons from your owners manual below seem to grudgingly accept possible need for brief choking when warm...


3. If the engine is cold,
turn the carburetor adjusting
rod one full turn to the
left to give it a richer mixture
for starting. This rod
serves both as a choke for
starting and as an enriching
adjustment. Next pull back
the rod, at the same time pressing down on the starter button
with your foot. The instant the engine starts, withdraw your
foot from the starter button and release the choke rod, next
advance the spark lever about half way down the quadrant.
When the engine warms up, turn the adjusting rod back to the
right. Never drive continuously with adjusting rod more than
~turn open. (See Adjustment of Carburetor, Page 24.)
When starting a warm engine, do not pull back the choke
unless the engine fails to start on the normal mixture as there
is a possibility of flooding the engine with an over rich mixture
of gas. lf you should by accident flood the engine, open the
throttle and with the choke rod in normal position, turn the
engine over a few times to exhaust the rich gas.

[BILL WILLIAMSON]

If it's consistent, don't wurry about it. Just wurry about when the check's coming & WHEN will SUPPER be ready?
Bill W.

[Mitch//pa]

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a properly tuned motor and carb should fire without pulling the choke rod hot. if you have to do that something is off, be it a vacuum leak or carb issue, engine mechanical issue.
a trained eye and ear should be able to come up with a solution.
how are the plugs burning?

[Mitch//pa]

after shutting a car off there is some residual fuel laying in the intake ports that will aide restarting especially a minute later. i am wondering if your running to lean

[Tom Wesenberg]

I would first check the carb idle circuit.
Even slow hand cranking will start a warm engine without having to choke it.

[TerryH]

Once warm, mine will,start without the choke even two hours later. I agree, something is not quite right.

[Mike V. Florida]

Now that you know that it is a "problem" you need to decide if it is a big enough one to warrant taking things apart again. I know it would gnaw at me knowing it was not right, but that just me.

[w.michael]

Hmm. I've been pulling the choke every time I start the engine, warm or cold, for over fifty years on three different Model A's--and in fact on every Model A I've ever driven. And after rereading the instruction manual, as Bruce posted above, I'm not sure anything is "wrong." The only time I don't pull the choke is when I get a rare "free start." If it runs good and idles good, don't touch that carburetor! JMHO, others may disagree.

W. Michael

[jmeckel]

Check the passages to the secondary well and the tiny holes in the brass secondary well. Also check the passageways from the cap jet. I use a gas welder tip cleaner of the right size to clear all of these passageways after they are glass bead blasted and then soaked in a carb boiling tank. There is a lot of junk that gets in these passageways that must be completely removed or your carb will not work like it should. Sometimes I have to repeat the process more than once. Everything must be shiny clean any little piece of rust etc. and you will have issues.

Also make sure your float level is right, too low of level will be another cause of problems.

[Gary WA]

Could be His is Ok-all others need attention! Happy Easter!!

[BILL WILLIAMSON]

Originally Posted by w.michael

Hmm. I've been pulling the choke every time I start the engine, warm or cold, for over fifty years on three different Model A's--and in fact on every Model A I've ever driven. And after rereading the instruction manual, as Bruce posted above, I'm not sure anything is "wrong." The only time I don't pull the choke is when I get a rare "free start." If it runs good and idles good, don't touch that carburetor! JMHO, others may disagree.

W. Michael

Seems that every A Model has it's own PERSONALITY With it's Zenith-2, Minerva would start WITHOUT choking, inside the carriage house! Only time I needed to open the GAV, was when it was below 28 degrees here.
Bill W.

[mshmodela]

As newbie, I've learner or my Ms. Daisy has "learned me" that when she's warm, less than 1/4 GAV, and try no choke at all.... And never more than 3 cranks either warm or cold --less you piss her off with a flood of gas.... Still learning this old gal...