carburetor zenith 12848 problem after reconstruction

1959 - 1978, M151, M151A1, M151A2, Technical questions and discussions, regarding anything related to the M151.
Rickf
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Re: carburetor zenith 12848 problem after reconstruction

Post by Rickf » Mon Jan 24, 2022 2:56 pm

Ok, I see a pattern here now. In order for these vehicles to run, and start, correctly the entire engine has to be set correctly. That include engine timing at 6 degrees, (Which is right on the line) the timing can only be set after the points are set because the points will change the timing depending on where they open and close. Ignition points should be set to .017-.022. Valves need to be set to .015 warm. The carburetor idle mixture is the very last thing you set on the engine and it is the screw on the flange of the carburetor where it bolts to the manifold. On later carbs this is covered with a metal cover that needs to be very carefully drilled and popped out to get access to the adjusting screw below.

You REALLY need to download the 2320-218-20 manual and go to the engine description and maintenance (in vehicle) section. That tells you everything you need to know.
Now, a little hint, In the original service they used a 160 degree thermostat. If you go to a 180 degree thermostat you will get better power, you will lose the flat spot and you will also not get anymore condensation in the oil.
1964 M151A1
1984 M1008
1967 M416
04/1952 M100
12/1952 M100- Departed
AN/TSQ-114A Trailblazer- Gone


lolo France
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Re: carburetor zenith 12848 problem after reconstruction

Post by lolo France » Wed Jan 26, 2022 2:40 pm

thank you very interesting, I am in France here it is "mm" or "cm", do you know how far the ignition points should be set to .017-.022

Rickf
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Re: carburetor zenith 12848 problem after reconstruction

Post by Rickf » Wed Jan 26, 2022 4:39 pm

Sorry, can't help you there but this will help. Click this link and there is an interactive converter. I did the .017 conversion and copied it but it would be better if you actually did it so you see the whole thing.

https://www.engineeringtoolbox.com/inch ... d_751.html

How many millimeters in an inch?
1 inch (in) = 25.4 millimeter (mm)
1 millimeter (mm) = 0.0393700787 inch (in)
1
mm


= 0.0394 inches

.017
in


= 0.432 mm

Lengths Units Converter
1964 M151A1
1984 M1008
1967 M416
04/1952 M100
12/1952 M100- Departed
AN/TSQ-114A Trailblazer- Gone

Rickf
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Re: carburetor zenith 12848 problem after reconstruction

Post by Rickf » Wed Jan 26, 2022 4:42 pm

And it is best to set the points a little wide since as the rubbing block wears they tend to close up. I believe .017 is the minimum isn't it? I would go for .018 or .019. Also, on that note be sure to put some lubricant on the points cam for that rubbing block.
1964 M151A1
1984 M1008
1967 M416
04/1952 M100
12/1952 M100- Departed
AN/TSQ-114A Trailblazer- Gone

lolo France
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Posts: 46
Joined: Fri Aug 20, 2021 7:49 pm
Location: france

Re: carburetor zenith 12848 problem after reconstruction

Post by lolo France » Thu Jan 27, 2022 9:06 am

thank you very much for your help, it's almost the thickness of a match

Rickf
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Re: carburetor zenith 12848 problem after reconstruction

Post by Rickf » Thu Jan 27, 2022 9:11 am

For 60 years or more a matchbook was used to set the points on older American cars. The setting for them was .016. :mrgreen: :mrgreen:
1964 M151A1
1984 M1008
1967 M416
04/1952 M100
12/1952 M100- Departed
AN/TSQ-114A Trailblazer- Gone

markrdje
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Re: carburetor zenith 12848 problem after reconstruction

Post by markrdje » Thu Jan 27, 2022 1:31 pm

Finding a match book is a problem now!LOL!
change user name to mark

lolo France
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Re: carburetor zenith 12848 problem after reconstruction

Post by lolo France » Wed Feb 09, 2022 7:03 am

I received a set of new screws and I am going to overhaul my distributor, I think to remove it to clean it well and adjust the spacing of the screws,

What should be paid attention to before taking out the dispenser? stall the engine maybe?

lolo France
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Location: france

Re: carburetor zenith 12848 problem after reconstruction

Post by lolo France » Sat Feb 19, 2022 6:27 pm

I finally found the problem which did not come from the carburettor but from the distributor! I found by wanting to adjust the opening of the screws that 2 cams out of 4 opened the screws at 0.17, in fact the axis of the distributor was bent! possible cause a spring of the flyweights were weak,

my mutt to regain its full power now!

I just have one question, where is CYLINDER NUMBER 1 located? transmission or radiator side?

here is my engine with my new igniter

Image

Rickf
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Re: carburetor zenith 12848 problem after reconstruction

Post by Rickf » Sun Feb 20, 2022 4:35 am

Just so you know, those two springs on the weights are different from one another. One will be tight and heavier than the other one. That is correct.
1964 M151A1
1984 M1008
1967 M416
04/1952 M100
12/1952 M100- Departed
AN/TSQ-114A Trailblazer- Gone


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