The Ford Barn - View Single Post - Zenith

Benson · 06-06-2021, 01:41 PM

There are 3 adjustment screws normally on a stock Model A Zenith.

1. IAS Idle Air Screw on upper casting (45 degree angle) for adjusting Idle mixture.

2. GAV Gas Adjustment Valve lower casting (45 degree angle) on the same shaft as the choke lever.

3. The idle speed adjustment screw on throttle shaft

Then there is a 4th possibility.

4. A "T" handle on bottom coming out of the normal drain plug. (90 degrees to the casting)

This is not stock and if it is there it is the cause of this problem.

Which one are you turning 4 1/2 turns?

06-06-2021, 01:41 PM	#15
Benson Senior Member Join Date: May 2010 Posts: 2,599	Re: Zenith - 1 Carburetor There are 3 adjustment screws normally on a stock Model A Zenith. 1. IAS Idle Air Screw on upper casting (45 degree angle) for adjusting Idle mixture. 2. GAV Gas Adjustment Valve lower casting (45 degree angle) on the same shaft as the choke lever. 3. The idle speed adjustment screw on throttle shaft Then there is a 4th possibility. 4. A "T" handle on bottom coming out of the normal drain plug. (90 degrees to the casting) This is not stock and if it is there it is the cause of this problem. Which one are you turning 4 1/2 turns? Last edited by Benson; 06-06-2021 at 03:57 PM.