Technical Carter Carb Choke question

Hey guys I’ve got a stock ‘63 impala with a Carter carb. I want to make sure my choke is set correctly. This is where it’s at. When I go to start. I step on the gas pedal once and then let it go. I haven’t driven it in several days these are the pics. Please advise on what needs to be done.
Thanks

 

...and it stays wide open after stepping on the accelerator pedal?

 

If the engine has sat overnight and cold,the choke blade should be closed with a slight spring tension,once gas pedal is pushed to the floor and released before starting. The other picture shows the choke fast idle cam and adj. screw. There is usually a spec. for that setting ,usually 1500 rpm while positioned on the 2nd highest cam on the ramp.

 

Show a pic of the p***enger side of the carb

 

(1) Pick a time when the ambient is between 65 and 70 degrees F. and the engine is cold.
(2) Remove the air cleaner
(3) Loosen the three screws that prevent the choke cover from rotating.
(4) Move the carburetor throttle linkage manually to wide open, and release.
(5) Move the carburetor throttle linkage manually to approximately 1/2 open and HOLD
(6) With your other hand, rotate the choke cap in the "LEAN" direction until the ****erfly drops open.
(7) Now rotate in the opposite direction until the choke ****erfly rotates to the closed position. The ****erfly should just touch closed, with zero tension on the ****erfly. HOLD the cover in this position.
(8) With your third hand, snug (overtightening will break things) the three screws retaining the cover.
(9) Release everything, and replace the air cleaner.

To start a cold engine (depending) on the Reid Vapor Pressure of the fuel you are using, this method generally works.

(1) Press the footfeed to the wide open position, then release. Remove your foot from the footfeed.
(2) Crank the engine for appoximately 3 seconds, and stop.
(3) Press the footfeed to the floor twice, and then release and remove your foot from the footfeed.
(4) Crank the engine, which should start almost immediately, and run at the fast idle of 1500~1800 RPM.

The engine may or may not, depending on the wear of the fast idle cam, automatically drop as the engine warms and the choke releases. If the fast idle cam is worn, it may be necessary to "blip" the footfeed to allow the engine speed to drop.

The fast idle RPM should be set immediately after starting a cold engine.
The curb idle RPM should be set after the engine acquires full operating temperature.

Things that can go wrong:

There are three common problems with exhaust heated automatic chokes:

(1) After 30~50 YEARS, the exhaust burns through either the heat tube of the exhaust manifold in the area of the heat tube allowing raw exhaust to enter the choke housing on the carburetor. This is quite apparent by removing the choke cover. The inside of the choke housing should be relatively clean; the presence of exhaust with quickly turn it brown with residue and rust.

(2) The choke vacuum source p***age becomes clogged with carbon, preventing source vacuum from evacuating the choke housing

(3) A previous owner (the current owner of any vehicle never makes these mistakes) used a 12 foot cheater bar when tightening the choke retaining screws (number 8 above), causing the choke housing to warp and not hold a vacuum.

It is quite easy to determine if either (2) or (3) has happened, by removing the heat tube at the choke housing, and holding a Kleenex to the opening in the housing from whence the tube was removed. If working properly, a running engine should supply sufficient vacuum to the housing to hold the Kleenex in place. If not, either condition 2 or 3 is present, and must be addressed.

If the carburetor has been downgraded with an electric choke then (2) above is still important, but (1) and (3) are not.

Jon

 

I just loosened the choke valve but the ****erfly won’t move.

 

The other thing that happens, that Jon didn't mention, is that the vacuum piston that "pulls off" the choke gets stuck. If you remove the black round cover, and then the baffle plate, you'll see the linkage that connects the piston. To see if this is stuck, or maybe another part of the choke is stuck, you might need to disconnect that linkage that goes up to the ****erfly.

I hope you have a lot of patience, because you'll need it.

 

So I live in San Diego is the choke even necessary?

 

If you have trouble keeping it running when the engine is cold, then it would help. If that's not a problem, then don't worry about it.

 

As Jim mentioned, the internal choke pull-off (the piston inside the choke housing) can stick, but I have yet to see one stick unless raw exhaust is getting to the choke housing.

If you removed the choke cover and the ****erfly won't move; then it will be necessary to determine why.

First take pictures of the linkage, then disconnect the linkage on both sides from the choke ****erfly, and test to see if it moves.

If it does, hook up the linkage on the side opposite the choke to see if the ****erfly will move. (If not, check the fast idle adjustment).

If it does, disconnect this side and hook up the linkage on the choke side and again test.

If the piston is stuck, preventing the ****erfly from moving; start the engine, and place a finger over the heat tube where it is disconnected from the choke housing. You should feel nothing. If you feel pressure, then the choke tube / exhaust manifold will need work.

And Jim mentioned patience, which is always a good trait when diagnosing an issue; but these tests are no difficult, one simply has to isolate the issue.

In San Diego, you may not need the choke, but if you do have an exhaust leak, it certainly should be repaired, whether you use the choke or not.

Jon

 

1st let me say thanks for your wise advice. I have had this car for 10 months with this carb. 90% of the time it fires right up. When it sits for a week it takes a long time to fire it up. I had exhaust leaks that I found and sealed up using a vacuum cleaner in reverse. I also cleared out stove pipe in the exhaust manifold. The tube is new. Tomorrow I will investigate to see why that valve is stuck and move onto the next steps to getting this running properly.

 

While the choke is not working, you may be chasing the wrong culprit if you have the slow start only after the car sitting for a week; all of the fuel might be evaporating out of the carburetor. This is common with what p***es for gasoline these days.

Jon

 

Are you taking about newsoms winter blend snake fluid?

 

So I squirted carb cleaner in the choke valve and it loosened it up. The choke tube is hot and the ****er fly is moving more open but slowly.