will not idle

K

k gilmore

Junior Member
Replaced the carburetor, new manifolds, gaskets, checked timing, and replaced the distributor with a "rebuilt" pop-out. The car will not idle; any suggestions?
 
K, more info is needed here.

What is a rebuilt pop-out distributor?

Does the engine start and run at fast idle or any other speed?

Was the replacement carb known to be good? such as off a running car?

Is the carb a stock Zenith that has been rebuilt / cleaned?


Have you set the base idle air adjustment?
 
Have you done a compression check on all the cylinders. Something I am guilty of, I tried setting the idle with the engine running too fast. These puppies idle slow and you have to adjust the idle with the engine idling slow other wise the idle jet has already been bypassed.
 
Either some jets in the replacement carburetor are clogged or the idle circuit is out of adjustment. To adjust the carburetor, screw in the speed adjustment screw until the engine will keep running. Then adjust the mixture screw for the highest rpm. Then back out the speed adjustment screw a little and again adjust the mixture adjustment screw. Repeat until you get a low, reliable idle.

See https://model-a.org/default.html
 
What is happening is that the car will start and now idle fine after some adjustments. When the wheels are on jack stands it runs fine in all speeds. when taken off the jacks, the car goes fine in reverse, but when moving forward it will want to stall, and buck.

I replaced the switch with a pop-out rebuilt by Dick Crabtree. The cable is too short, and I suspect that the short cable is part of my issue. Steve Becker on his website no longer offers the longer cable for the pop-out (1931).

I have run model A's for more than 30 years and never have I encountered a problem such as this. I may go back to a distributor without the pop-out.

I am open to any solutions!
 
Maybe the float in carb? Is okay in one direction but not the other has me thinking the float might be opening and closing the needle and seat if it's happening when the car is moving.
 
Smokedtires said:
Maybe the float in carb? Is okay in one direction but not the other has me thinking the float might be opening and closing the needle and seat if it's happening when the car is moving.
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I thought of that too, but before I put in the Pop-out switch, it was running fine. I changed out the carburetor with one from my other A with no luck, still the same, but I will look into the carb issue, it's a Zenith 2 and its clean; I can and will change out the float.
 
I do not think the problem is in the carburetor. I think your ignition has a problem. Based on the work you have done and the parts you have replaced, you should start investigating based on probabilities:

1. Initial timing is wrong. Easy to do. Get the #1 cylinder on TDC with the timing pin and then remove only the round cap on the distributor body. Look at where the brass tab on the rotor is pointing, relative to the #1 silver pin inside the distributor body. Look around for the drawing by Marco that helps you assess the rotor position, if it is close to correct. If not, set it again with the spark lever all the way up.

2. Confirm polarity of coil is correct for the way you have installed the battery in the car. Positive ground? Then the coil post labeled with the "+" needs to feed through the ignition switch down to the distributor points. Should be a red wire from coil + post to the switch, then armored cable down to the distributor.

After these, go back to the carb. Check float level, check for debris clogging up a jet.
 
Try another set of spark plugs. You made no mention of replacement. Maybe? One or two are bad. It has happened to me.
 
K, when the car is bucking and stalling, what is the ammeter showing? An unintended ground in the primary ig circuit, which occurs after the primary coil winding will not blow the safety fuse. It may, if the stall is long enough, show up as a negative needle indication on the ammeter.

Make sure the screws on your switch are not loose or touching the fuel tank. take the bezel loose and try driving with it hanging down. Check the coil connections, and the connection of the cable at the distributor might be too loose or too tight.

There is a bypass cable for proofing out a switch issue. It is sold by the vendors. If you have a modern upper plate, it's not difficult to bypass the switch by running a wire from the + side of the coil to the condenser connection point in the distributor. You would have to shut the car off with fuel, the safety switch, or the coil wire though.

Luck to ya
 
Too many changes at once. don't start taking a carb apart that you know ran (and idled) well on another car.

Asked before ................. We get that you changed the popout switch assembly. Did you also replace the distributor?
 
k gilmore said:
....before I put in the Pop-out switch, it was running fine.
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There is your focal point moving forward. Try bypassing the popout with another ignition cable or whatever you were using before and go from there.


lrf said:
Could you have screwed the pop-out end that goes into the distributor, in to far? LRF
Click to expand...

That is only a problem when using the flimsy repro lower plates and the "modern" condenser. A stock condenser adds rigidity to the insulated tab on the lower plate and you can thread the ignition cable in as far as you want.
 
Thanks all for the advice. I am going to replace the condenser as suggested. The short cable that came with the pop-out will be replaced (thanks Dick Crabtree). Other than that, it's wait and see cause once I send off the short cable, I have to wait for it to return.

Also, a great thanks to Dick Crabtree, his work is amazing.
 
k gilmore said:
Thanks all for the advice. I am going to replace the condenser as suggested. The short cable that came with the pop-out will be replaced (thanks Dick Crabtree). Other than that, it's wait and see cause once I send off the short cable, I have to wait for it to return.

Also, a great thanks to Dick Crabtree, his work is amazing.
Click to expand...

You can always "hot wire" it, while you wait for the pop-out with the longer cable. :D
 
I agree with bypassing the ignition switch. I keep a jumper in my tool kit as a just in case for myself and for others.

One more thing to check would be the condition of the flexible wire under the plate in the distributor. Might have frayed wires or a loose connection.
 
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