EICSB112 – Carb Tech

EICSB112 – Carb Tech

The Zenith 36NDIX (Pinzgauer) and the Zenith 32NDIX (Unimog) carburetors are very similar. Hence we have combined this section on Carb Tech. A proper carb rebuild is crucial to keeping your truck running properly. The purpose of this section is not to walk the reader through a rebuild, but to give some tips and comparisons that might come in handy.

  • 1. All Carb kits are not created equal. Does your carb need a repair or a rebuild? Be sure to check out the section below on Carb Rebuild Kits.
  • 2.If you are going to rebuild your Carb, do it properly. Installing the new rebuild kit with floats and then not bothering to Set the Float Level is bad mechanics. The float level tool is widely available and worth the extra money to do the job correctly. (On a side note we rarely see float failures, usually just not adjusted properly.)
  • 3. Repairing/Rebuilding your carb is not the only fuel system maintenance that should be performed. Your fuel system also includes fuel filters (more than 1), fuel tanks, fuel pump, tank selector valve (if equipped) and fuel lines. If you have debris in your carb, cleaning out the jets and bowl is only a short term solution. Bottom line, maintain the full system.
  • 4. The inside of the fuel tanks can peal. The resulting orange flake debris can cause lots of problems. Lead additives tend to increase this problem. (Lead additives are unnecessary with the Unimog and Pinzgauer, but you would be surprised how many people use it “for good measure.”) If you are getting orange flakes in the filters take care of your tank. At a minimum remove the tank and completely clean and flush it. If the problem is bad, send the tank out and have it sealed professionally.
  • 5. Jet your Carb for the area you primarily run in. You want to run it leaner at higher altitudes, and richer at the lower altitudes. Most Unimog 404′s and Pinzgauers come jetted with 140′s. Those living above 5000′ may want to consider 130-135′s in the Carb. Most dealers can supply the required jets for your area. Changing out the jets is a quick process, so carrying an extra set is not that uncommon.
  • 6. Idle mixtures screws are quite often damaged. If you have never checked them on your truck, its time. The most common problem is that they have been screwed in too far damaging the ends. Replace as needed.
  • 7. Check for loose Nuts/Bolts. The Pinzgauer is very prone to this. Specifically check the float bowl cover screws, and the base mounting nuts. Quite often they have worked themselves loose and can cause serious damage by creating an air leak and overheating a cylinder.
  • 8. Carb Gaskets are known to Weep gas. This primarily occurs on the top float bowl gasket. Usually the culprit is that the float bowl cover and float bowl are not perfectly flat. Any good rebuild should include “stoning” these two pieces. If it is a persistent problem you may want to move to one of the slightly thicker aftermarket gaskets available.
  • 9. 50% of the Carbs we open up have had the O-ring installed on the Low Speed Jets incorrectly, or are missing the O-ring completely. When installing the new O-rings, they are installed on the low speed jets after the threads, not prior. For a better explanation call the shop.

Carb Kits

All Carb kits are not created equal. Know what you are getting. A call to your local parts supplier looking for a “Carb Kit” may get you one of many different kits available. Specifically ask your dealer if this is an original kit, aftermarket, modified aftermarket, and what it includes. Does the kit include the floats, jets, etc.

50+ Piece OEM Rebuild Kits

$110-$130 These kits are complete Carb rebuild kits that include: every brass fitting, all gaskets, high speed jets, low speed jets, float valve, floats, accelerator pump, idle mixture screws, and all orifice fittings. Of note is the following:

  • These kits are more difficult to find and more expensive, but they are a true Rebuild kit.
  • Depending upon the condition of your Carb, it may not need a complete Rebuild Kit and a Repair kit will do.
  • In our opinion these are the highest quality and most complete kits available for the Unimog and Pinzgauer

20 Piece Aftermarket “Porsche” Kit

$25-$50 range: Yes the 32NDIX carb was used on some of the Porsche 356′s. Some of the gaskets will match up, and the kit is reasonably priced. We consider this kit a good “Gasket” kit.

Of particular note should be the following: The FLOAT VALVE and the ACCELERATOR PUMP are incorrect. A number of trucks have fallen victim to the local mechanic rebuilding their carbs with these kits.

  • The float valve in this kit is usually a 140-160. The Unimog requires a minimum 200. Where this is noticeable is on the top end power. If your carbs have been rebuilt and you have lost some of your top end power, inquire as to the kit used.
  • The accelerator pump in this kit has a shorter plunger. Symptoms of this are a hesitation off the line when putting your foot into the peddle.

26 Piece, Unimog/Pinzgauer Aftermarket Kits

Usually priced from $65-$85: These kits are available from a couple of the Unimog and Pinzgauer dealers. Of note is the following:

  • This kit is an aftermarket kit produced for the Pinzgauer and Unimog. It is not a complete kit, but a very good Repair kit. Quality is good.
  • This kit is not a Rebuild Kit as it does not include many of the internal brass fittings. Many of the fittings it does not have are orifice fittings that do clog.
  • The Bowl Gasket in this kit is made of slightly thicker gasket material. This is a GOOD THING that combats the standard carb weeping when the bowl and bowl cover surfaces are not perfectly flat.
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