carb

[63cub]

tell me about zenith carbs just recently put one on my cub it works great but i would like to know more about it

thanks

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[Rudi]

David:

The GSS-1411 which can be found on the Cub Manual Server under Blue Ribbon Service Manuals, will give you a lot of the technical stuff on the Zenith Carb. The TC-37F Parts Manual will show you how it all goes together which is especially good when it comes time to overhaul your carb is also a good source of info.

As for pros and cons or other anecdotal info, I have yet to be able to find anything in numerous searches on the net. At least on the Cub version of the Zenith.

[mbrowne]

Hi,

When you put on the new Zenith, did you have to open up the manifold hole? Also, do you have pictures of how you rigged the linkage: throttle and governor?

Malcolm Browne
713-962-5214

[WKPoor]

When you put on the new Zenith, did you have to open up the manifold hole

You don't need to change anything about the original manifold, however there is a manifold available to match the Zenith and the hole looks to be just a smiggin larger. I was just studying that 2 days ago.

[Carm]

I just doubled up the gaskets for my zenith

[Lurker Carl]

Here's a short and sweet synopsis of the Zenith carburetor:

The Zenith updraft series 68 is made of cast aluminum. It is used as original equipment or replacement carburation for engines in the 25-170 CID range and has been in production for over 45 years. Because it is a universal design, it comes in hundreds of configurations to adapt to each specific application (such as manifold flange, throttle bore, jet size, venturi size, etc.) and may have specific features for automotive engines not needed for agricultural or industrial applications.

Because of the configurations available, be leery of used Zeniths unless the seller will guarantee the carburetor came off the machine he is claiming it fits. The mods prevent you from grabbing a Zenith series 68 off a Gravely and mounting it on your Cub unless you're willing to swap out or adapt the parts that will make it fit AND run like it should. To add to the confusion, Zenith uses sequential numbers to identify part sizes without regard to measure, thus #7 throttle bore is 7/8", but a #7 flange is 2 1/4" mounting hole spacing. The same sequential numbering system applies to calibrated fittings such as jets, air bleeds and discharge nozzles. But the venturi is measured in millimeters so a #17 venturi is actually 17 mm. You may acquire a Zenith the fits the manifold but has components that are not designed for peak performance on a Cub engine.

[SundaySailor]

On the older Ford and Chevy six cylinder engines, they had a carburetor that if I remember correctly, was similar in size to the IH carburetor. In specific, the carburetor for a 135 CID, 170 CID Ford engine, and the 235 CID Chevy engine that was so good and popular. Has anyone ever tired any of these carbs to see if they would fit? It would be interesting if they did fit because it would open the door for more parts availability. Just wondering.


Rick

[Lurker Carl]

Automotive carburetors don't work very well with governed, low rpm engines - the air flow is too low for efficient operation.

[beaconlight]

All the old cars I worked on were down draft carbs. A cub is up draft.


Bill

[John *.?-!.* cub owner]

Never had any dealings with the older Ford carbs, but I thought I remembered the 235 Chevy being a downdraft.

[Lurker Carl]

The Model T and 4 cylinder Model A Fords were updraft. I'm sure there are others, but most automotive carburetors are down or side draft. One could be converted for use on a Cub but it really seems like a lot of trouble since Zenith still makes a suitable carburetor that bolts right up.

[beaconlight]

Ok I said old but I didn't think about that old. I was in the 1936 Ford and Chevey, Plymouth range.

Bill