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MG MGB Technical - Zenith Carburetor Problem

I am a new MGB enthusiast and have a problem with the carburetor. I recently bought a partially restored 79 MGB, engine and carb rebuilt by previous owner, and am having some several woes and am a just learning the ropes. The carb is a Zenith 175 CD and the autochoke seems to be stuck. When opening the unit the lever which fits into the spring coil is unable to be moved.
The surrounding parts are the insultaor choke and heat mass I believe if that helps a bit. The lever moved freely before. Can anyone suggest how to free this without further damage?
I am a female and am just learning the ropes so please bare with me.


Thanks,
EAM


EA Martin


Follow this link to Rick Jaskowiak's superb
description of the autochoke and rebuild procedure.

Even if you convert to the manual choke (which
I personally prefer), the main autochoke body is
retained and should be rebuilt as Rick describes.

http://www.paulbunyan.net/~jasko/choke/
Ronald

Thanks! I found this extremely helpful!
I'll get back with results.

Elizabeth
Elizabeth

Elizabeth. I have a 19 year old daughter, an engineering major at University of Arizona, who learned to drive on an MGB. She also learned a lot about working on them while helping me to prepare and maintain her car. First of all, get some workshop manuals. The best, in my opinion, are the ones published by Robert Bentley Publishing. This workshop manual also contains a reprint of the factory Driver's Handbook which will answer quite a number of questions you may have. If money is tight, the Haynes workshop manual is a less expensive and, to me, less useful manual.

Join the MG Enthusiast's Club. It is free and will give you access to the archives, a source of many years of compiled wisdom.

Consider the "Weber conversion". This is replacing the existing Z-S carb with a Weber carb and intake manifold. I purchased a new 79 MGB in Novemeber of 79. It had the Z-S carb and there was a dealer network to maintain it properly up until 82-83. It never worked as well as the SU carbs which were first used on the MGB, nor as well as the Weber conversions I am running on my current 79LE and my daughter's 77. Currently, the "newest" Z-S carbs are 23 years old and yours is 24 years old. They need to be rebuilt about every 35,000 miles or every three to four years. Nothing mechanical has an infinite rebuild life. Unless you, like Ron, are required to run the original Z-S carb for emissions testing requirement reasons, I would recommend you replace it. My experience is that I could never tune an old Z-S to the levels of emissions performance and engine performance that I can tune the Weber to. Here in Arizona, the Weber is acceptable to the emissions testing people and my cars have been passing with very low emissions readings while providing good performance. Les
Les Bengtson

Les, not to change the subject,but............

I thought that LE's were only in 1980?

I just purchased a 5-79 LE.
But the side stripes were removed for the [awful] paint job. Or they were never on the car. I have no real history of this car. Except the previous owner was intending to V6 it.

Were there 'real' '79 LE's?
Dwight
Dwight McCullough

Dwight. "To increase interest in the ageing MGB in the North American markets, the "Limited Edition" roadster (also known as the "Special") was launched in 1979 continuing into 1980" Clausager, "Original MGB" page 104.

You might contact the British Motor Heritage Institute Trust and get their certificate for your car. I believe they can be reached through this site. Supposedly, all of the black cars exported to North America were made into LEs, so a certificate showing the original color as black is a good starting point. The definitive check is to look at the tire pressure decal inside the glovebox lid. The standard cars had 165 tires and this is what is on the decal. The LE models had 185 tires as standard on the Triumph Stag wheels. The tire pressure decals reflect this change. So, if your tire pressure decal shows 185 tires, you, at least, have a real LE glove box lid. Moss, et al, sell the 165 decals for replacement purposes, but I have never seen the 185 decals sold. All of the other parts to create an LE out of any roadster are currently available. The North American MGB Register has a special sub-register for LEs available through their site which is, in turn, available from the home page of this site. Les
Les Bengtson

Thank you Les. I will find out.
Dwight
Dwight McCullough

More about California and probably Nevada emissions.

In theory, in California, you have to have a carb
of the same manufacturer and same number as originally equipped. In practice, I have never
been questioned about missing number tags on my
Zeniths.

Several people on the midget BBS have reported
passing with a single SU carb replacing the
single Zenith in California. As long as the carburetor is a
sidedraft with the same throat size, it will
probably pass. The SU conversion sold by VB
and now Moss would probably pass, although its
technically not legal in California.

In fact, someone on the Midget BBS claimed he
passed Calif. smog with a Weber DGV. Even though
it was obviously a downdraft, a lot of smog
testing stations are not that rigorous.

I read a while back that about 30 percent of
CA smog stations failed to pick up missing or
malfunctioning emissions equipment in random
tests.

I'm not endorsing swapping carbs, but my personal
opinion is that California emissions regulations
(in addition to most of our legislature) are beyond
brain damaged.
Ronald

This thread was discussed on 06/05/2003

MG MGB Technical index

This thread is from the archive. The Live MG MGB Technical BBS is active now.