Early Zenith Idle Jet # 10??

[James G.]

I'm restoring an early Zenith double venture carburetor for my carb collection. I mostly have focused on the aftermarket carbs for the Model A made in Russia, Japan, Argentina, etc. Plus, a goodly number made in the US. This carb, the double venture Zenith, is a bit unusual so I'm trying to restore one to original for the collection. I only need the idle jet # 10. That is the one Steve Pargeter specifies for this carb.
I'd appreciate your help so please look through your carb stuff and let me know if you have the #10 idle jet. I have a number of other Zenith/Holly carb parts to trade or I can strait purchase. Again, thanks for your help!
Jim Gregory
[email protected]

[johnbuckley]

A # 10 jet is 0.5 mm diameter, the #11 0.55mm dia ( you can do the math, I am sure, for 1/1000s of an inch, or google can!). The small 2035 cc engine that Ford Uk produced alongside the 3.3litre had a #10 jet as standard. If the carb is an early one without the brass well in the secondary chamber the original jet would have been slightly longer than the later ones ( these had to be made shorter to fit in the well). I have run a#11 jet in a 2035cc engine successfully...I've probably got a #10 in the shed but I don't know if it's stamped and it is almost certainly the later length which was about 2mm ( about 1/10 inch) shorter and anyway hardly worth shipping costs! Interesting though.

[Joop]

From Rex Reheis Carburetor book


..

[Ron in Quincy]

In addition to the #10 Idle jet, the very early Zenith used a #18 (.o36)Compensating jet, forged steel throttle and choke levers, the choke lever did not have a bottom leg. As said before there was no removable secondary well .

A later #11 Idle jet (.021) will work just fine if you want to use the carb for driving.

Other features of the very early Zenith is a boss and pin on the back side of the lower housing for retaining the double ventuti, no boss and pin on the front side and a raised "Z" on the engine side of the upper housing, no "Z" on the front side.

I believe the forged steel levers are the most difficult to locate, when assembled a #11 idle jet cannot even be seen unless you open up the carb. Just my opinion.

Ron

[Benson]

1. How are the 20 degree throttle plates marked?

1a. I was told that they were unmarked ... problem is most of the Repros are also unmarked!

2. Or is the 20 degree plate an urban myth?

3. Will an 18 1/2 degree plate work in the early upper casting?

Thanks

[johnbuckley]

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1) and 1 a ) never knowingly seen one
2) Don't know
3) Yes

[Richard Lorenz]

From my memory, the 20 deg. plates have no markings. The 18 1/2 deg plates were marked that way so that people would know that they are different from the early 20 deg plates.