13T - Carburetor Adjustment

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Darin Hull
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13T - Carburetor Adjustment

Post by Darin Hull » Sat Apr 25, 2020 11:24 am

Gentlemen,

I’m learning about every aspect of the T, starting with the fundamentals which seem so basic to you all but are new to me.

A section of a book I’m reading discusses how to adjust the fuel mixture of the carb with the knob which comes though the firewall. It says, “A rich mixture is indicated by a heavy black exhaust smoke having a disagreeable smell. When this condition is manifested the needle valve regulator on the dash should be screwed down or to the right until the engine begins to misfire, then the gasoline feed is gradually increased by opening the needle valve in the other direction slowly to the point where the motor runs steadily and at a high rate of speed with a full throttle opening, at the same time, there being no evidence of smoke in the exhaust.”

Does that sound good to y’all? Or does anyone have some different guidance?

Thank you for your time,
Darin


Scott_Conger
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Re: 13T - Carburetor Adjustment

Post by Scott_Conger » Sat Apr 25, 2020 11:43 am

Nothing's changed in 95 years.

Welcome to the affliction.
Scott Conger

Tyranny under the guise of law is still Tyranny

NH Full Flow Float Valves
Obsolete carburetor parts manufactured

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Bill Robinson
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Re: 13T - Carburetor Adjustment

Post by Bill Robinson » Sat Apr 25, 2020 11:45 am

Sounds good to me. That’s how it’s done.


Original Smith
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Re: 13T - Carburetor Adjustment

Post by Original Smith » Sun Apr 26, 2020 11:17 am

A good starting point is to gently screw the adjustment down until it seats, and then open it 1 1/2 turns.

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DanTreace
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Re: 13T - Carburetor Adjustment

Post by DanTreace » Sun Apr 26, 2020 3:21 pm

The Ford Owner's Manual is a useful resource too. Vendors supply reprint of these.

IMG_3361 (600x431) (580x417).jpg
IMG_3361 (600x431) (580x417).jpg (159.35 KiB) Viewed 2276 times
And setting for initial starting of a fresh rebuild of the popular Holley NH, where the needle valve is new and new seat, these positions have worked the best IMO.


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Re: 13T - Carburetor Adjustment

Post by Allan » Mon Apr 27, 2020 3:25 am

Darin, the sweet spot can be approached from the lean side or the rich side. I like to wind the needle in, [lean] until the car runs poorly. Then note how many turns it takes in the opposite direction to again have the car run poorly [too rich]. Then wind the needle down again 1/2 as much as you wound it out. That way you approach the sweet spot from the rich side. I reckon that is preferable to being on the lean side.

Allan from down under.

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