61 Comet stalls at idle when auto choke plate opens

[Pete W]

Hi,

I finally got my Comet to start running. When I rebuilt the carb I didn't tighten down the nut from the auto choke to the choke plate and it was stuck in the wide open postion(being a newb that is were I thought it was supposed to be on a cold engine..DOH!).

The problem I have now is when the engine warms up and the choke plate opens a little the car runs rougher and rougher until it stalls out. I checked for vacuum leaks and I have found none. Everything on the carb is tight. I did put a little something "miricle oil" in the gas tank a while back and there still might be a little in there. I guy told me to put it in a work. I'm at a loss for why it is doing this.

Pete

 

[fordconvert]

Will it run off idle? If it does it may just be idle mixtures and idle stop issues. Otherwise it could be a float level issue assuming you got everything clean and back together the right way.

 

[Pete W]

TJ,

I runs great when I put on the gas. It does seem to speed up and slow down a little bit at idle. Someone said that is a vacuum leak issue but I have checked and checked and everything is tight, at least around the carb.

Pete

 

[Anonymous]

it sounds to me like your throttle blade is in the wrong place in reference to your transfer slot. its a tiny rectangular slot just above the throttle blade and its intended purpose is to help transition from idle to part throttle or wot. this is adjusted with the idle SPEED screw and the blade should just touch the slot. check this first then check your mixture screw for best lean idle. the transfer slot gets used the absolute most at just off idle and cruise which sounds like where your problem is.

 

[Pete W]

Hi,

The carb is a Holley 1904 single barrel. There are three screws to adjust. The fast Idle cam screw, the slow idle screw and the mixture screw. How do I adjust it to do what you are talking about.

Thanks

Pete

 

[Anonymous]

im much more familiar with the later models than yours but i would imagine that would be the slow idle screw as the fast idle is basically there to hold the throttle more open whilst the engine is in the process of warming up. take your carb off and look at the bottom where the transfer slot is and adjust your screws acordingly till the blade just starts going into the slot. then with the engine not completely warm adjust the fast idle screw till it smooths out. ( i am assuming that the mixture isnt miles off base here) remember i am more familiar with the later ones like the 1940 and 45 (that my slant sixes had) but that should do it. line your slot up first then leave it alone---you may have to play with the fast idle and mixture a bit since after all it is a 47 year old carb. worthy of note too is that after so many years sometimes the the hole around the throttle shaft will need to be bushed to take up wear/slop, and on occaission you may run into a warped base plate that leaks even when tight.

 

[jamyers]

Is your ignition system dead on - timing set, good plugs, points, wires?

If so, then on the carb (glass float bowl, right?), I'd start by spraying something flammable (wd-40, carb cleaner, etc) around the base of the carb with the engine running. If you've got a vacuum leak, the engine rpm will change when it sucks the spray in. Just don't set yourself on fire, use common sense.

If you can't find any leaks, then shut it off, and holding the choke full open to clear the fast idle can, back the slow idle speed screw out until the throttle stops closing. Look down the carb throat with a flashlight to make sure the throttle plate is centered in the bore, and closed all the way around (easier with the carb removed, but...).

Then turn the idle speed screw in until the throttle starts to move, then in maybe another 2 turns.

Turn the idle mixture screw all the way in, go easy and don't crank on it or you'll regret it. Once it bottoms out nice and easy, back it out 2 full turns.

Start the engine, and let it get up to operating temperature - you may have to manually run the choke / throttle, hopefully not.

Now you need a vacuum gauge, available at a decent parts place for maybe $10. You can do the following by ear, but it's a lot easier with a gauge to help.

Once the temp gets up, the choke should want to open fully, and the engine *should* be running, but probably roughly. Turn the idle mixture screw out then in, noting how far you turn it. You're looking for the smoothest idle you can get, which should also be the highest vacuum reading. Then set the slow idle speed screw for the specified idle rpm. THEN go back to the idle mixture screw, and do it again. you may have to adjust these two screws a couple of times, maybe not.

When you're done, the engine *should* be idling smoothly, the carb is adjusted. THEN you can set the choke.

If not, then I'd take the carb off, take it apart (those are simple/easy), and CLEAN CLEAN CLEAN it out, spraying carb cleaner into and through every passage, hole, nook and cranny. A carb rebuild kit is about $15, you might have to wait a day or so on one.

OH, and another place to look for a vacuum leak / problem is the PCV valve, iirc it's a dinky metal checkvalve coming out of the carb adapter plate. Take it off and make sure it's not gunked up, or better yet replace it if you can find one locally.

 

[Pete W]

Hi James,

Thanks for the tip! A few questions.

I can't find the PCV valve? Is it on a Holley 1904 carb?

How do I set the choke after it is running smoothly?

Thanks,

Pete

 

[jamyers]

Oops, just looked at my Ford manual, and the initial idle mixture screw setting is 1 to 1.5 turns out, not 2.

PCV valve? Oops #2. I'm thinking '62, in '61 they may not have had a pcv valve - if you do (and it's like my '62), it's a small metal fitting coming out of the front of the carb adapter plate, with a hose or steel line running over to a fitting in the block just in front of and above the distributor. If you don't have one, it's a good idea to add one, they help engine life and reduce a ton of emissions. '61 may not have a pcv, might even just have the draft tube sticking down from that block fitting.

You've got an automatic choke? To set the automatic choke...well, there are specs in carb kits, and I just looked in my Falcon manual, but apparently Fords all came with manual chokes...dang.

In general, there should be a reference line scribed on the black choke cover, that'll match up with some other lines on the choke housing. Generally, start with the choke housing line centered in the housing lines (make sense?), which should have the choke wanting to close when cold, and open when warm - and you adjust it a little bit at a time to find the best setting (take a couple of cold days).

To set the fast idle, the general method is to get the engine warm, then move the fast idle cam/link into position, then adjust the fast idle screw to get about 1100-1200 rpm warm.

----------------------------------

I was re-thinking your problem, and it sounds like you've either got a vacuum leak or your idle passages are restricted/clogged. Has the carb been apart and cleaned lately? I see you rebuilt it, but if it's had gas sitting in it for several months, it could be varnished. Also, is it a "remanufactured" carb (which often means it was beaten on by a some ham-fisted moron who doesn't care...)?

Hope this helps, anything else I can do, let me know!

 

[jamyers]

Just did some looking, and the carb kit for a '61 Comet 170 with or without auto choke is GP Sorensen Carburetor Kit, Part Number: 96115C. Napa wants $35, Parts America wants $29, AutoDrone wants $24.

 

[Anonymous]

I did put a little something "miricle oil" in the gas tank a while back and there still might be a little in there. I guy told me to put it in a work. I'm at a loss for why it is doing this.

You put oil in your gas tank?

 

[Pete W]

James,

I rebuilt my carb abuot a month ago. I was sure to clean everything in carb cleaner and blow out the ports with compressed air. There still might be a vacuum leak somewhere. Tomorrow morning I'm going to go through the steps that you showed. If it still does not run right I'll search for a leak again.

Pete

 

[woodbutcher]

Hi Steve-O,probably Marvel Mystery Oil.It`s a goob top cylinder lube.
Leo

 

[Pete W]

Thanks to ya'lls help she's up and running!

Fixing the stuck choke plate and adjusting the timing/carb was all it took. I'm sure future problems/suggestions are just around the corner and I'll be back with more questions. (<:

Thanks again,

Pete

 

[addo]

That is a cool car!

 

[jamyers]

Glad to be able to help out.

Nice ride, I love the fender skirts!

 

[Mercury Mike]

I was in your exact same boat. Glad you got it figured out. Did you end up having a vacuum leak at all?

 

[Pete W]

Hi,

I couldn't find one but I do notice a whistling/whining niose when I accelerate down the road. It's not constant, just when I step on the gas hard. Other than that it runs fine. I think I could do a little fine tuning with the carb and timing to get it closer to perfect.

The problem a have at the moment is that my lifters are rattling again. I had someone fix it last year and I have no more than five hundred mile since and they are doing it again. I'm going to read the manual this afternoon and probably pose the question on this board seeking advise.

Pete