Zenith Main Jet Size ?

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on-to-berlin
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Zenith Main Jet Size ?

Unread post by on-to-berlin » August 6th, 2018, 2:00 am

How do I see the size of the main jet and the idle jet on my 13660? I read Wiki and saw that there are two different sizes. Size 28 and 30. Somewhere it says the size is written on the jet.
I had no luck finding it so I wanted to check but have now idea how to measure it. Any adivice highly appreciated!

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1939 Harley Davidson U
1944 Harley Davidson WLA
1944 Willys MB
1969 Ford Mutt A1
1973 AM General Mutt A2

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rickf
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Re: Zenith Main Jet Size ?

Unread post by rickf » August 6th, 2018, 8:40 am

The main jet is usually stamped on the side of the jet and the jet you show in the picture is the emulsion jet not the idle jet. The idle jet is the one that will fall out of the bowl when you invert it and I have never seen any numbers on any of them. Unless we are using different nomenclature. There were only two different sizes of idle jets , 12 and 15, the 12 being the A1 12848 carb and the 15 being all of the 13660 series carbs. If it is the jet you show then they are not interchangeable.
Just as an aside, You really do not need to worry about the main jet size since this motor will never flow enough air to fully max out the flow of the main jet.
1964 M151A1
1984 M1008
1967 M416
04/1952 M100
12/1952 M100- Departed
AN/TSQ-114A Trailblazer- Gone

on-to-berlin
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Re: Zenith Main Jet Size ?

Unread post by on-to-berlin » August 6th, 2018, 3:29 pm

O.K. so generally all of the rebuild kits have the right jets for 13660 and the 12848? If I change the jets then all of them so they correspond? I still do not quite get it.
1939 Harley Davidson U
1944 Harley Davidson WLA
1944 Willys MB
1969 Ford Mutt A1
1973 AM General Mutt A2

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rickf
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Re: Zenith Main Jet Size ?

Unread post by rickf » August 6th, 2018, 3:39 pm

I am pretty sure none of the kits come with a new main jet. As far as the emulsion jet the only kits I have seen in the last ten years are for the 13660 carbs but all of the parts with the exception of that jet will work. All of the gaskets and seals are the same. I personally have never had to replace the one way valves, I test every carb I do but I have never had a bad one way valve. They are tricky to replace so if it is working I leave it alone. I have not used a military kit in a long time, I use kits directly from Zenith that use diaphragms that are compatible with todays gasolines. The military kits are at the newest 30 years old. The kits I use do not come with new jets of any kind since the jets just do not go bad, they are metal and they don't wear out. If they are cleaned properly without poking wires through them then they will last forever. If you do have to poke something through it to clean it use a bristle from a paint brush.
1964 M151A1
1984 M1008
1967 M416
04/1952 M100
12/1952 M100- Departed
AN/TSQ-114A Trailblazer- Gone

on-to-berlin
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Re: Zenith Main Jet Size ?

Unread post by on-to-berlin » August 7th, 2018, 2:36 am

Rick, that sounds good! I will try that. Since I am in Germany I do not know how and where to get civilian gasket kits here. Where do you buy them in the US?
1939 Harley Davidson U
1944 Harley Davidson WLA
1944 Willys MB
1969 Ford Mutt A1
1973 AM General Mutt A2

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rickf
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Re: Zenith Main Jet Size ?

Unread post by rickf » August 7th, 2018, 8:40 am

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

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Horst
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Re: Zenith Main Jet Size ?

Unread post by Horst » August 8th, 2018, 4:02 pm

Horst

1972 USMC M151A2 w/ROPS (ex Barstow) and M416
1962 M201 and trailer
1966 GTO,1982 E350 Skoolie, 1987 SJ413, 1987 911
Gone: 2xM35A2c, Unimog 404S, Hanomag AL28, DKW Munga

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