I give up

[1930artdeco]

Just thought of this one. This happened to me once, I had the glass sediment bowl screwed on to tightly. I don't know how I did it but once I loosened the screw nut about a turn or so fuel started flowing again.

Mike

[Woodie1]

I did replace the air idle mixture screw because of slight scouring on the tip. It turned out that the replacement was about 1/8" shorter than the original screw. Didn't solve the problem though. I would like to get a little more fuel in the bowl but I don't see how. When the top half of the carb is held upside down, the solder line on the float looks to be very evenly parallel to the mating surface. If I remove a washer from under the float valve then I have an uneven condition. When I drop the bottom half of the carb & put a ruler inside to measure the gas, it is about 1" below the mating surface of the carb. I know that's too low.
I just tried starting fluid & it killed the engine. I thought it was idling fast enough. I did not hear the engine rev up faster.

[Woodie1]

I put some new spark plugs in & it runs a bit smoother now but the idle is still too fast. If I slow it down the engine dies.

[Y-Blockhead]

Originally Posted by Woodie1

I put some new spark plugs in & it runs a bit smoother now but the idle is still too fast. If I slow it down the engine dies.

I know you said everything is fine with the carburetor but to me your symptoms keep pointing to a clogged idle jet or idle circuit.

I see no where in this discussion what kind of carburetor you have. Idle mixture adjustment on a Marvel is opposite that of a Zenith or Tillitson.

[Woodie1]

The carb is a Zenith. I can see through the idle jet & blow through it. The passages in the idle circuit will let me run a wire through them.

[1crosscut]

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I just tried starting fluid & it killed the engine. I thought it was idling fast enough. I did not hear the engine rev up faster.[/QUOTE]

If spraying starting fluid made a change to how the engine runs, in your case it killed the engine you have a leak at the manifold that needs to be fixed.

I'm not sure why you are continuing to fuss with the carburetor if you have already switched to a different carburetor and still had the same problems.
Perhaps I'm missing something.

[JayJay]

Originally Posted by 1crosscut

I just tried starting fluid & it killed the engine. I thought it was idling fast enough. I did not hear the engine rev up faster.

If spraying starting fluid made a change to how the engine runs, in your case it killed the engine you have a leak at the manifold that needs to be fixed.

I'm not sure why you are continuing to fuss with the carburetor if you have already switched to a different carburetor and still had the same problems.
Perhaps I'm missing something.[/QUOTE]
Agree.

[dave in australia]

o you know anyone else with an A without this issue? If you do, ask if you can swap over the carb for a trial. If the problem goes away, it was the carby, if it stays, then look elsewhere.

[1crosscut]

Any success in getting it running well again?

[petew]

I have had cars act like this with ignition components like coil or condenser that were failing but not yet dead.

[old31]

Woodie, .18 on the distributor is way too much. You should have .03-.05 up and down movement.

[JayJay]

Originally Posted by old31

Woodie, .18 on the distributor is way too much. You should have .03-.05 up and down movement.

I think you’re off a decimal point - up and down play should be 0.003”, not 0.03”. But I do agree, 0.018” is excessive. Not sure how you do that unless you omit the spacer at the bottom?

Whether it would affect the idle - I’d look more for the bushings being worn or missing, and therefore affecting point gap. With that much vertical play it appears someone has been there, and no telling what’s what. There should be negligible side-to-side wiggle of the shaft.

[Woodie1]

I put a different carb on today & was able to stop the car without it quitting. This tells me it is the carb. Upon taking the carb apart again I noticed the end of the idle jet was slightly mashed on the end. I measured it's length to an old original jet & found it to be about .020 longer than the original. When the carb was assembled without the gasket & the idle jet in place, the carb halves would not meet. I was hoping I had the problem solved. The car runs slightly better but now the air mixture screw must be almost seated to get the best or fastest idle. I guess there is still an air leak. The throttle shaft is snug. The threads for the air mixture screw seem tight. The mounting bolts are snug & so is the bolt that holds the carb together.

[Wick]

I went through this same situation a few years back. Carburetor swaps didn't change anything.
I changed the intake and that solved the problem. I bead blasted it and found a Crack at the vacuum port.
Also look at this.....If you have a air maze on, remove it. Check Carburetor for cracks and try 2 Carburetor to manifold gaskets.

[Dr Foot]

Recheck plug gap..if too wide engine won't idle down smoothly.

[Woodie1]

No air maze. Plug gaps are set at.030 as per others suggestions with a high compression head. This last carb swap ran well so I would think that rules out the manifold.

[1crosscut]

Originally Posted by Woodie1

No air maze. Plug gaps are set at.030 as per others suggestions with a high compression head. This last carb swap ran well so I would think that rules out the manifold.

Have you fixed the leak at the manifold that you found when you sprayed starting fluid around it?

If not you will be always be having problems with how your car runs.

[Woodie1]

I don't think there is a manifold problem since the last carb had it running well. I want to figure the original carb problem out now.

[Thodge]

In a previous post you mentioned that the fuel level in the bowl was 1” from the top when you checked it. Did you adjust the float level to address the low level yet? Maybe the problem isn’t too much air from a vacuum leak but not enough fuel from a fuel level or idle jet problem. Does richening the GAV a bit have any effect on the stalling at stops. I notice that mine has much less tendency to drop the rpms at a stop if the GAV is opened 3/8 turn vs 1/4.

[Synchro909]

Take the carburettor off and look down the throat. There is a small hole on the float chamber side of it right where the throttle plate rests at idle. With the throttle closed, that hole should be half covered by the plate. If it is not, back off the idle stop and the screws holding the plate to the shaft. Holding the throttle arm in the closed position It should not be against the idle stop), tap the plate with the handle of the screwdriver to make sure it is centred properly. Reset the idle stop and the hole should be half covered. I have sometimes filed the plate a little to get that and other times, put a little solder on it, then file to get the desired result.
That is an often overlooked item and often not mentioned in threads like this.