Mixture Control Setting?

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Model T Ford Forum: Forum 2017: Mixture Control Setting?
Top of pagePrevious messageNext messageBottom of page Link to this message  By Tom Lawthers on Saturday, June 10, 2017 - 09:57 pm:

Okay, I just got back to getting my 26 Touring going again and have run into a problem.

Seems to me, I use to set the mixture control at approximately 1 1/2 turns out to start on a NH carb. After start, I would turn it down to about 1 turn open from close.

The other day, I started the car up and it kept bogging down from what seemed to be to much fuel. I pulled the plugs and found that they were all black soot from an over rich mixture. Today, I cleaned the plugs and restarted the car. I had to bring the mixture control down to 1/2 open from close to make the car run smoothly. It ran very well, however, I am thinking that at this mixture control setting, something is wrong internally with the carb? Maybe the float is sinking? Needle valve not seating?

I operate the vehicle in the mountains at 4500 feet.

Any ideas?

TIA

Tom L.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mark Gregush Portland Oregon on Saturday, June 10, 2017 - 10:47 pm:

maybe just some crud that cleared itself in the spray needle opening. If it's bogging down because of rich mixture, well then reach down and close it up some. These Ford carbs are not set and forget, that's part of the driving experience.
I have a friend that no matter what you tell him, he gets in starts the car and pulls the spark lever down leaves the spray needle adjustment alone, which may be fine on the flat, but he keeps saying it's missing going up hill because he never changes the spark or spray needle from where it's set. As it is, most of the time it's running rich and I have to keep cleaning his plugs. :-)


Top of pagePrevious messageNext messageBottom of page Link to this message  By Tom Lawthers on Sunday, June 11, 2017 - 10:54 am:

Thanks Mark,

I would think that it was crud in the fuel tank since there are some remnants of rust in the tank after I took it out of the car and cleaned it.

The vehicle has been sitting for 6 months while I cleaned the tank, replaced the transmission bands and other assorted items.

Unless my memory has gone, I remember driving this car with the mixture control somewhere in the ball park of 1 turn open from closed.

Would density of altitude require as much as a half a turn to lean to make the car run properly?

Tom L.


Top of pagePrevious messageNext messageBottom of page Link to this message  By David Menzies on Sunday, June 11, 2017 - 11:45 am:

Spray a little water around your spark plugs and see how much leakage you have, they frequently leak some, some more then others. If the leakage is excessive it will affect the mixture. They are pipe threads and don't seal that well. Because of the leakage there will be many variable positions. My 26 starts at one turn and runs at 7/8 turn. I had a rusty thread in the head and a bad leak causing excessive popping and some erratic behavior and I sealed it with an epoxy material, after that it settled down.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Norman T. Kling on Sunday, June 11, 2017 - 06:04 pm:

At a higher elevation you should run a bit leaner. There is less air so you should also have less gas. Try adjusting clockwise until it begins to sputter, then back counterclockwise until it runs smooth. That should be the best position for running. It differs with every carburetor and also with altitude.

If you turn all the way closed and it still sputters, then maybe you have a problem with the carburetor float.
Norm


Top of pagePrevious messageNext messageBottom of page Link to this message  By Paul Bourgeois,Aldergrove BC,Can. on Sunday, June 11, 2017 - 08:24 pm:

David ,a friend of mine who has been running his 26 T coupe for about 50-60 years told me a few weeks ago about taking a strip of aluminum foil and wrap it around the threads of the plug. A few of mine have a leak and that's what he suggested.
Haven't done it yet, trying to fix a small problem with the reverse spring in the trans.


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