Carburetor

[lawrence coldren]

Need Advice, The QuatraJet carburetor on my 1974 is in bad need of rebuild.
I have heard that there modifications that should be done at the time of
rebuild. I would like to have my carburetor rebuilt and returned to me.
1. What are these modifications?
2. How can you tell if they have been accomplished?
3. Are there any carb rebuilders that GMC people frequently recommend?
4. What might I expect to pay for this work?
5. How difficult is it to do yourself? Taking it apart is no problem.
6. Where is the best place to get a complete rebuild kit?
Thanks for all the sage advice.
Larry Coldren
1974 Canyon Lands
1959 Elva MK-IV
1955 Austin Healey
1954 Siam Special H mod

 

[brent covey]

Hi Larry-

Subject: GMC: Carburetor

> Need Advice, The QuatraJet carburetor on my 1974 is in bad need of
rebuild.
> I have heard that there modifications that should be done at the time of
> rebuild. I would like to have my carburetor rebuilt and returned to me.

Theres a few people doing this- I would not discourage you from attempting
this job yourself either- its not too hard to do-

> 1. What are these modifications?

Main Jet 0.002"- 0.004" larger, slight enlargement of ports for idle circuit
are two usual modifications. I'd skip the latter as its primarily needed for
well worn engines and smoother drive range idle, not a real issue in the
GMC. Throttle shafts are a common wear point, and the secondary air
adjustments are seldom perfect.

> 2. How can you tell if they have been accomplished?

Hard to detect without having done so yourself- total disassembly and
inspection is needed.

> 3. Are there any carb rebuilders that GMC people frequently recommend?

I'd try to do it yourself- or failing that have your VERY OWN ORIGINAL
rebuilt, Greg Kalkhoff from the Toronado list is one pretty good carb guy
does nice work inexpensively.

> 4. What might I expect to pay for this work?

Parts to do a fairly good job of a mildly worn carb are worth about
$65-$100, including dashpots and a float.
The labour varies widely, but $200-$300 total isnt too much if they do
wonderful work. Just a carb kit is ~$20.

> 5. How difficult is it to do yourself? Taking it apart is no problem.

Its extraodinarily easy to do yourself, and I highly recommend it- I'd be
glad to walk you thru it and I'm sure many GMC net people will have good
advice also.

> 6. Where is the best place to get a complete rebuild kit?

Try your local AC Delco Jobber warehouse, or NAPA etc. It will be in stock.
You'll ned the carb number for your model also.

Parts List-

Fuel Filter
Float
Gasket Kit
Choke Pulloff(s) (also called 'vacuum break')
Carb Base Gasket
Carb Cleaner to soak parts in (buy enough to submerge the carb)

Hope this is helpful! Write if I can help, Larry.

Brent Covey
Vancouver BC

 

[bartz paul]

Larry:

I had my carburetor overhauled by A & G Carburetor, Oak Park IL (a suburb on
the W side of Chicago), 708-386-9804, in Aug 1996. It cost