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New zenith carbs

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Topic: New zenith carbs

Posted By: oldchalmersiron
Subject: New zenith carbs
Date Posted: 14 Feb 2012 at 7:49pm

I am looking to buy a new universal zenith carb for my WD from yesterdays tractors (part #12522, availible from many other places also). I was wondering what your opinions would be on this carb and how it compares to the older original Zenith's. The 2 older Zenith's I have used always seem to leak gas or not run right even after I cleaned them out the best I could and rebuilt them. Any help is greatly apreciated.

http://www.ytmag.com/12522_30.htm" rel="nofollow - http://www.ytmag.com/12522_30.htm

Replies:

Posted By: Steve in NJ
Date Posted: 14 Feb 2012 at 9:03pm

The problem with "universal" carbs is just that. They fit a number of applications. Not only will you have an Erector set of bracketry on top of the unit for all the applications it fits, the most important part is that it may not be jetted correctly for your particular application, and therefore possibly be to lean or to fat. (rich) That's the chance you take with "universal" carbs. My personal feeling is that if you stick with the OEM carb that was designed for your application, you won't have any problems. The old carbs actually perform quite well when they're rebuilt correctly. It's super important to get all idle and enrichment circuits clean and clear for these carbs to perform to their max. You also need to have a very, VERY clean fuel system to supply clean debris free fuel. Dirt, water, and rust is the biggest problem with any carb, new or rebuilt. We offer rebuilding services if interested. Its your choice, but as I said, I'd stick with the OEM carb....

mailto:Steve@B&B" rel="nofollow - Steve@B&B

Posted By: Chalmersbob
Date Posted: 14 Feb 2012 at 9:50pm

I find the Marvel Schebler carb to be more durable and less likely to leak. I have them on my WD, D14, D15, B, C, G and CA. They are made out of cast iron, not pot metal. Bob

Posted By: Burgie
Date Posted: 15 Feb 2012 at 6:12am

I like the Marvel the best. Don`t care for the Zenith.

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"Burgie"

Posted By: JimD
Date Posted: 15 Feb 2012 at 9:42am

For the most part I'm with Steve. I would prefer a good rebuilt OEM carb over a universal. But sometimes, they can be hard to find in usable condition. I usually have some cores around, but they are getting thin. I've sold a number of the universal carbs, and never had a complaint other than figuring out the linkages.

JimD

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Owner of http://www.OKtractor.com" rel="nofollow - OKtractor.com PM for an instant response on parts. Open M-F 9-6 Central.

We have new and used parts. 877-378-6543

Posted By: stu(ON)
Date Posted: 15 Feb 2012 at 11:27am

The main help that I can provide is mostly from personal experience. It would be best to confirm that the carb you favor is a correct model for the WD, as Steve alludes to regarding jetting:

http://www.thecarburetorshop.com/Tracallischalmers.htm" rel="nofollow - http://www.thecarburetorshop.com/Tracallischalmers.htm

Follow the instructions in the following manual as best you can:

http://www.antiquefarming.com/PDF/carburetor.pdf" rel="nofollow - http://www.antiquefarming.com/PDF/carburetor.pdf

Zenith is in the second part of the manual. Be sure to remove the venturi and clean out the tiny passage behind it as well as the gunk around it. Jets & nozzles like to be removed with the proper tools. Better to leave a stubborn one in place than to destroy it unless you are prepared to deal with the consequences. Tip cleaners for oxy-acet torches offer a range of diameters for very careful cleaning of all passages that don't get replaced.

Steve would blast your carb clean with glass beads but you may have to make do with a bucket of todays weak carb cleaner. So be it. There may be shaft packing that won't enjoy a soaking.

I expect that you would have replaced the primary needle valve & seat. If you now have a neoprene tipped needle, it seems a little tougher to eliminate the leaking that you refer to. I believe that you would find that many folks now adjust the float level by carefully bending the tang so that it closes the needle a little sooner, rather than later. This will eliminate the leaking of gas through the primary bowl gasket half way up the carb. The reason for this adjustment may be that modern gas includes alcohol which has reduced buoyant force, &/or modern gaskets differ in thickness, &/or the geometry of modern needles & seats is slightly different from original. If you find that your WD starts easily without choke on a cool day, it probably is over-fuelled and will benefit by this adjustment.

If you find that the carb ices up excessively under load, you would benefit from providing more radiant heat from the block, probably by ensuring that thermostat and temp gauge are working and then using the manual shutters to keep the coolant temp way up in the green range.

Going through these steps has provided me with a very functional 10981 Zenith on my '51 WD. I work it very hard on a brush hog in the summer and it never runs short of fuel (follow Operators Manual instructions for setting idle & main jet screws). Acknowledging Steve's thoughts about proper jetting, if I had a good core and just couldn't rebuild the carb properly myself, considering the cost of a new universal Zenith, I would prefer to send my carb to Steve for a rebuild specific to my need.

HTH,

stu