How do i adjust my choke?

B

Born2Lose

Active member
I have a '62 Mercury 144 and i have some cold starting problems even here in SoCal. I think its because my choke is not closing all the way. I have read here its supposed to only be open about and 1/8th of an inch and its more like a 1/4". I know the fuel pump is ok since it was replaced a few years ago and i also recently dissasembled and checked it for problems. Here are the links to two pictures..one of the choke fully closed and one of the side of the carb.
WARNING: They are large files..that's why i didn't directly post them..and yes i know the carb looks scummy at the base :)

Thanks


http://img520.imageshack.us/img520/2264/img5335.jpg

http://img520.imageshack.us/img520/8365/img5334.jpg
 
right but how do i physically set that choke? what adjusts the blades?
i realize it has something to do with the spring on the side but how.
 
Real simple: loosen the screws on the side of the carb around the black choke coil. SLOWLY turn the black plastic cover looking thing. Tehre shodul be what looks like a large screw driver slot in it. Rotate so the choke flap JUST closes at regular outside temp. Then tighten the screws. The carb is designed to open the flap a small amount when the engine is just started. As the engine warms, if the tube is hooked up correctly, the flap will slowly open.

There should also be on the side fo the carb a small lever that will hold open the throttle plate. This is called "high idle". As the choke plate slowly closes, the lever will fall away and let the throttle plate go back to its normal position. Also there should be some type of adjustment to the high idle speed. There is a spec on the rpms. It usually set when the engine is warmed up to operating temp.

I purchased my car from North Carolina, and the choke was not functioning the first nice Fall day when I brought it to Michigan. One other problem I had was the internal passages that supplied vacuum to the choke coil were blocked. So the heat from the exhaust manifodl never made it to the coil; and it needs this hat to open correctly. So make sure that heated air is being drawn thru the coil.

tanx.
 
mugsy":247wpye8 said:
Real simple: loosen the screws on the side of the carb around the black choke coil. SLOWLY turn the black plastic cover looking thing. Tehre shodul be what looks like a large screw driver slot in it. Rotate so the choke flap JUST closes at regular outside temp. Then tighten the screws. The carb is designed to open the flap a small amount when the engine is just started. As the engine warms, if the tube is hooked up correctly, the flap will slowly open.

There should also be on the side fo the carb a small lever that will hold open the throttle plate. This is called "high idle". As the choke plate slowly closes, the lever will fall away and let the throttle plate go back to its normal position. Also there should be some type of adjustment to the high idle speed. There is a spec on the rpms. It usually set when the engine is warmed up to operating temp.

I purchased my car from North Carolina, and the choke was not functioning the first nice Fall day when I brought it to Michigan. One other problem I had was the internal passages that supplied vacuum to the choke coil were blocked. So the heat from the exhaust manifodl never made it to the coil; and it needs this hat to open correctly. So make sure that heated air is being drawn thru the coil.

tanx.
Click to expand...

One problem with that..i seen no black plastic cover of any kind. Did you look at the picture? Thanks.
 
See where the choke tube attaches to the body of the carb? There should be a black plastic cover, under a metal retaining plate that has two screws in it. That's the choke coil you have to rotate to close the choke flap.

I tried to copy the pictue from another post on the 1940 carb, but it won't let me... :x I hate computers... :evil:
 
mugsy":u9f4jfbe said:
See where the choke tube attaches to the body of the carb? There should be a black plastic cover, under a metal retaining plate that has two screws in it. That's the choke coil you have to rotate to close the choke flap.

I tried to copy the pictue from another post on the 1940 carb, but it won't let me... :x I hate computers... :evil:
Click to expand...

Sorry about my carb ignorance. My other car that has a carb is not only a big four barrel but it's chokeless. I'll poke around. I also found this diagram on a carb service site but it's kinda small.

ford1962falcon3.jpg
 
The pic you just posted is for a manual operated choke. A cable attaches to the choke operating lever, runs through the choke control cable bracket assembly, through the firewall, and is mounted to the dash....nothing automatic about it...all hand operated.
 
Red arrow is pointing at choke housing. Loose the three screws that old retaining ring, and turn housing.

choke2.jpg
 
Adjusted it and now it starts like a champ the first time it cranks over. The problem is now it idles really high and doesn't come down when i tap the gas a few times. How long does the high idle take to drop down and will it drop down if i put it in gear? Also how do i turn it down?
 
No problem about learning about carbs' we ALL start out the same way.

The High Idle you describe is controlled by two things. The length o ftime its on is control by how much you turned the choke coil. There is a bi-metalic strip (spring actually) inside the housing. The more you turned the coil in the "rich" direction, the longer the choke will stay on.

The second adjustment is the actual speed of the engine while on high idle. Look on the opposite side of the carb from the choke coil. You'll notice that a lever onthe throttle plate is resting on a stepped lever on the choke shaft. With the 1940 carb GENTLY bend the lever on the throttle shaft to open/close the throttle. Now it is possible to bend the lever and damage it. So be very, very gentle. I typcially would hold the lever near the throttle shaft with one pair of pliars, and then grab and bend the end with another pair of pliars. You should be able to figure out which way to bend to open/close the throttle plate.

Keep us updated as you fix and tweek the carb.

tanx,
Mugsy
 
I think i probably just turned the choke a little to far in the "Rich" direction. It didn't move as precisely as i was hoping for. I'll have to adjust tomorrow when it's cooled down again.
It was idling really high and fast. I manually moved to lever to get it off the high idle cam because it just sounded too high and long. I'm guessing around 2000-2500 rpm. After about 2 or 3 minutes if i pressed the gas it would stay at a higher rpm for a few seconds then drop off and then after about 5 minutes it was back to normal and the throttle response and drop off was normal.
It'd be quite scary to drive it like that if the car wasn't warmed up. I even put in gear with foot on brake and E-Brake on and it still stayed at that high RPM.
I then hooked up my electronic timing light since it has a tach and turned down the idle speed but i couldn't get it down to 550 like the tune up chart says. But i did drop it about a hundred to 650 or so.
 
Is that 550 RPm in gear or in park?

In the picture do you see the cam that is held by the "E" clip? That has two steps on it. When the choke plate is all the way closed the long lever on the left (that's attached to the throtle plate) will be stopped by the highest step on the cam. That sets the "Fast Idle" speed. You'll also notice that there is a secondary (lower) step on the cam. That is the an idle speed between the high and normal idle. Once you set the fast idle speed, this second speed is all set too. No need to try an adust for that.
Set the fast idle speed when the car/engine is warm. Just move the lever and cam by hand.

The rod on the left is the choke pull-off rod. When the car first fires up the diaphram on the left will pull in and pull/move the rod to the left. It should open the choke plate just a little. This will prevent over choking, and the black smoke which is a result from a way too rich Air/Fuel ratio.

The rod on the right connects the choke shaft to the cam. You can also bend this to change the relationship between the choke flap position and the cam position. Again, use two pliers and slightly bend the rod but don't over muscle it, youll break it. Make surethe cam is free to rotate and doesn't stick. For best crb performance you want botht he choke plate and the fast idle cam to work in tandem.

tanx,
Mugsy 8)
 
Update:
When i got off work today and the car was nice and cold i had my wife hop in and push the pedal once to lock down the choke. I then backed off the choke so it just barely barely shut . My wife turned it over and it started up right away and was a slightly faster than normal idle but not crazy high like it was yesterday..woohoo.
Also i decided to check the air tube that goes to the exhaust manifold and it seems that at some point in its life it was broken at the manifold. I took it off cleaned it out, sanded the manifold a bit then stuck it back in and used some steel putty to seal it around the broken connector.

Thanks for all the help everyone especially mugsy for being so patient with me.
You guys rock..there are quite a few message boards out there..cough cough "The HAMB" cough cough..that if you don't know everything you're ridden out on a rail. Glad you guys are willing to help if someone is willing to learn.

THANKS! :D
 
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