The Stovebolt Site Forums The Parking Lot Big Bolts Carb rebuild kit for Zenith one barrell

Anybody got any idea's on how to find a rebuild kit for my 51 GMC 3 ton 270 ? I had it professionally cleaned and it still is
bogging down real bad and stalls out. I may need a new carb, but thought a rebuild might be worth a try.

Thanks, Troy

I bought a 55 first 1/2 ton with a 261 in it. Rebuilt the carburetor and it ran terrible. I learned the hard way.
It had a badly rusted (inside) fuel tank which means I had rust in the fuel lines, fuel pump, fuel filter and my newly rebuilt carburetor.
Replaced all of it and rebuilt the carburetor. Filled it with Non-Ethanol gas. Much better now but not ideal.
Next step is to replace the Rochester B with a Zenith.
For a Zenith, I would go to The Carburetor Shop website and see what model Zenith is listed for your truck.
There is a round brass tag on the top of your carburetor that has a stamped ID number.
For the ID number there is a matching kit number listed on the website as well as a phone number to call.
Carbking is much better on this than I am but you may need a few special tools.

Thanks guys, I will check for the id number and look at their website and try and figure it out. Then, maybe I can
get a kit ordered. I really appreciate ya'll getting back to me on this.

Troy

I'm watching this, I just bought a Zenith 228 yesterday for my 261, and the carb does need a rebuild.

Zeiniths are not hard to overhaul but you do need to take your time and make sure everything is squeeeky clean. Also accuracy in measurement counts. Fuel pressure is also important. Also bear in mind that alcohol in the gas will make things run leaner and if you're working the truck hard can have bad results. I have had valve stems stick and temporarily stuck a piston when I picked up a tank of gas with too much alcohol. One eights turn on the main jet fixed that. These zenith carbs were available with adjustable main jets. I have two. I don't know if they are available now but it's worth asking.

One thing often overlooked is throttle shafts. When these wear they leak air and the idle speed won't be consistent -- sometimes high, sometimes low sometimes rough sometimes smooth. You need a drill press and a reamer to do this properly as you need to get the bushings on both sides square and concentric. This is a job I used to do frequently on SU carbs and now need to do on both Zenith carbs on my 235 so I'll have to come up with bushings and a new reamer. I don't know if new throttle shafts are available and it's not something one can fabricate easily. Bushings should not be a problem. It's a ream to fit proposition. If someone knows where to get throttle shafts, I like to know.

Thanks so much for the reply 1Ton. I will be aware now a little more now of the details of this carb now as I go forward. I really
appreciate the sharing of your knowledge here.

Troy

Here is some reference info:

This link is from an IHC website. Zenith Bulletin Z-190-B for 28 and 228 models. Print date June 1950.
http://www.restoringcornelius.com/files/zenith_28_128_rebuild_manual.pdf

Zenith ID numbers for GMC with rebuilt kit numbers (sold at this site).
http://www.thecarburetorshop.com/TruckkitsG.htm#TkitGMC

also troubleshooting

http://www.thecarburetorshop.com/Troubleshooting.htm