Zenith Gas Supply to Secondary Well

[marc hildebrant]

Group,

My Model A runs fine with a Tillotson carb. When I stop the car does not stall and the GAV is out about 1/3 turn.

When I install my Zenith carb, the same car will stall after a stop and the GAV has to be out almost one turn. I live at Sea Level near the ocean.

The Zenith was rebuilt and flow tested prior by a large Model A supplier. At first, it ran O.K., now it has the "Stall when stopping" problem.

When I took the carb apart I noticed that the secondary well was not screwed down all the way to the bottom. It was up in the threads about two turns.

The compensator jet is new and seems clear. The passage into the secondary well seems fine from the GAV to the bowl.

I believe that the gas is not getting to the secondary well from the compensator jet.

Should the secondary well be screwed down tight?

Marc

[ryanheacox]

I would think the secondary well should be screwed in tight, if it isn't it can vibrate around and turn. All that I've seen have been tight.


Also, there is a thread here somewhere that states when the car stalls on a hard stop it is actually going too rich during the stop, not lean like you might think. The guy put a bunch of sensors on his car and posted the data here, pretty conclusive stuff and if nothing else probably the most interesting thread I've read on this site.

[ryanheacox]

Also, where on the Cape are you from? I'm seriously considering driving the A out there for our annual vacation in Dennis. Should be a fun drive if I leave early enough to beat traffic on the bridge.

[marc hildebrant]

I'm near the West Dennis Beach on the Cape. About 1\2 mile from the ocean.

Marc

[30 Closed Cab PU]

Originally Posted by marc hildebrant

I'm near the West Dennis Beach on the Cape. About 1\2 mile from the ocean.

Marc

Another possibility.



I also had teh stall at the stop, ended up being Nurex Distributor Wireless Plates were my problem. The "shoe" on the lower plate that makes contact with the upper plate was not making good contact, and the issue showed up during med - fast stops, or lugging up hills from a stop. Converted back to all original plates/parts - issue solved.

[Mulletwagon]

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Also, the idle mixture on Zenith carbs must be adjusted with the timing at full retard and idle speed minimized. The mixture screw actually controls air and not fuel, which means turning the screw in actually richens the mixture. Stalls at stops is often a matter of proper idle adjustment on Zeniths.