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[GMCnet] carburetor rebuild kit [message #145689] Thu, 06 October 2011 08:23 Go to next message
Steve[3] is currently offline  Steve[3]   United States
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Registered: September 2011
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I've got a '78 w/ 403 and can't seem to find the right rebuild kit for the carburetor. The parts guys are asking for the Rochester number but what I'm reading from the top of the carb (17058715) doesn't match any Rochester numbers that we can find. Any suggestions?

Thanks
Steve Thomas
'78 Eleganza II
Santa Cruz, CA
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Re: [GMCnet] carburetor rebuild kit [message #145692 is a reply to message #145689] Thu, 06 October 2011 08:37 Go to previous messageGo to next message
Ray Erspamer is currently offline  Ray Erspamer   United States
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The carb number is actually stamped on the drivers side of the carb. On a 78
with a 403, the carb number should be....

17058254 for standard emissions.

17058559 for california emissions.



Ray


Ray & Lisa Erspamer
78 Royale "Great Lakes Eagle"
Center Kitchen TZE368V101144
Wauwatosa, Wisconsin 53226
Email: 78GMC-Royale@att.net
414-745-3188
Web Site: http://ray-lisa.page.tl/



----- Original Message ----
From: Steve <stefansc@yahoo.com>
To: "gmclist@temp.gmcnet.org" <gmclist@temp.gmcnet.org>
Sent: Thu, October 6, 2011 8:23:25 AM
Subject: [GMCnet] carburetor rebuild kit

I've got a '78 w/ 403 and can't seem to find the right rebuild kit for the
carburetor. The parts guys are asking for the Rochester number but what I'm
reading from the top of the carb (17058715) doesn't match any Rochester numbers
that we can find. Any suggestions?

Thanks
Steve Thomas
'78 Eleganza II
Santa Cruz, CA
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Ray Erspamer 78 GMC Royale Center Kitchen 403, 3.70 Final Drive Holley Sniper Quadrajet EFI System, Holley Hyperspark Ignition System 414-484-9431

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Re: [GMCnet] carburetor rebuild kit [message #145693 is a reply to message #145692] Thu, 06 October 2011 08:42 Go to previous messageGo to next message
GMC Cruse is currently offline  GMC Cruse   United States
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Location: SE Michigan
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Ray Erspamer wrote on Thu, 06 October 2011 09:37

The carb number is actually stamped on the drivers side of the carb. On a 78
with a 403, the carb number should be....

17058254 for standard emissions.

17058559 for california emissions.



Ray is correct.

The numbers in the small circles are castings numbers, not the carburetor number.

Check on the drivers side of the main casting, right above the secondary throttle shaft.

There should be a carburetor number, Plant Code and Julian date stamped on the casting.

Mike K. '75 PB Southeast Michigan

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Re: [GMCnet] carburetor rebuild kit [message #145710 is a reply to message #145689] Thu, 06 October 2011 11:49 Go to previous messageGo to next message
emerystora is currently offline  emerystora   United States
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On Oct 6, 2011, at 7:23 AM, Steve wrote:

> I've got a '78 w/ 403 and can't seem to find the right rebuild kit for the carburetor. The parts guys are asking for the Rochester number but what I'm reading from the top of the carb (17058715) doesn't match any Rochester numbers that we can find. Any suggestions?
>
> Thanks
> Steve Thomas
> '78 Eleganza II
> Santa Cruz, CA

I would say that you do not have a GMC Motorhome carb. The internal passages are different between the motorhome carb and the automobile carbs.

From the number I would think that you have a 1978 Chevy carb for a manual transmission car. It is strange though that there would be a number 7 in the second position. Usually it is a 1 or 2 for federal carb ID, or it is a 4 or 5 for california emissions carb ID. Are you sure that is the number. {sometimes a 2 looks like a 7 if the stamping is not even}.

GM used seven different carbs for the GMC motorhome. 73 and 74 years had a carb #7043254
75 and 76 and early 77 had 7045254 except for California emision carbs which were 7045554
77 coaches with the 403 engine had 17057254 and California 17057559
78 had 17058254 and California 1758559

These carb numbers can be found on the left side of the carb, stamped on the flat surface close to the secondary throttle shaft.

There is also a date code (4 digits) stamped in the same area. 73 to 76 coachs had a number starting with 70
77 & 78 carbs start with 170.
Some parts for these carbs are quite different on the 170 from the 70. DO NOT INTERCHANGE parts between these two series.

One example is the primary metering rods. They are .080" shorter in the 170 series, they had a different taper to the rods and these carbs used different sizes of primary jets.
The rods for the 70 series carbs will be stamped D-50. (7046338) I am told that this was used ONLY in the GMC motorhome carbs. The 170 series are different. All GMC carbs used the same secondary metering rods. These will be stamped with a CJ. The primary jets for the GMC at your elevation should be .070". (7031970)

The proper power spring for the GMC is #7036019 which has an operating range from 4" to 8" of vacuum.

One problem that some people have had is the use of gaskets from an unknown kit. There are changes in the air passages in the carbs and it is easy to install a gasket that covers an air passage hole and that will make the carb perform improperly.

The Delco overhaul kit for the 73-74 is 7046812. For the 75-78 (non Calif) it is 17051886 but I don't know whether these will work with your carb.

Emery Stora
77 Kingsley
Santa Fe, NM


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Re: [GMCnet] carburetor rebuild kit [message #145776 is a reply to message #145689] Thu, 06 October 2011 23:35 Go to previous messageGo to next message
Steve[3] is currently offline  Steve[3]   United States
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Thanks to everyone for all the help. My know-it-all parts guy has never steered me wrong and he swore the numbers were on the top.

Steve Thomas
78 Eleganza II
Santa Cruz, CA
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Re: [GMCnet] Carburetor [message #314470 is a reply to message #145689] Sat, 11 March 2017 23:42 Go to previous messageGo to next message
BobDunahugh is currently offline  BobDunahugh   United States
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The carburetor in our 78 403 is 17058559. Sometimes carb numbers change during the year. This GMC was built in January of 78. Our other 78 403 GMC was built in December of 77. I believe there's 122 VIN's between them. I'll check the carb numbers on it tomorrow. Be interesting.

Bob Dunahugh
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Re: [GMCnet] Carburetor [message #314478 is a reply to message #314470] Sun, 12 March 2017 08:17 Go to previous messageGo to next message
Bruce Hart is currently offline  Bruce Hart   United States
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FYI
Handy reference for carb numbers!

http://www.carburetion.com/Number/bynumber.asp

On Sat, Mar 11, 2017 at 10:42 PM, Bob Dunahugh wrote:

> The carburetor in our 78 403 is 17058559. Sometimes carb numbers
> change during the year. This GMC was built in January of 78. Our other 78
> 403 GMC was built in December of 77. I believe there's 122 VIN's between
> them. I'll check the carb numbers on it tomorrow. Be interesting.
>
> Bob Dunahugh
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>



--
Bruce Hart
1976 Palm Beach
Milliken, Co
GMC=Got More Class
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Bruce Hart 1976 Palm Beach 1977 28' Kingsley La Grange, Wyoming

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Re: [GMCnet] Carburetor [message #314480 is a reply to message #314478] Sun, 12 March 2017 08:26 Go to previous messageGo to next message
Bruce Hart is currently offline  Bruce Hart   United States
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For carb kits and parts go here.

http://quadrajetparts.com/quadrajet-carburetor-rebuild-kits-c-128_33.html?sort=3a



On Sun, Mar 12, 2017 at 7:17 AM, Bruce Hart wrote:

> FYI
> Handy reference for carb numbers!
>
> http://www.carburetion.com/Number/bynumber.asp
>
> On Sat, Mar 11, 2017 at 10:42 PM, Bob Dunahugh
> wrote:
>
>> The carburetor in our 78 403 is 17058559. Sometimes carb numbers
>> change during the year. This GMC was built in January of 78. Our other 78
>> 403 GMC was built in December of 77. I believe there's 122 VIN's between
>> them. I'll check the carb numbers on it tomorrow. Be interesting.
>>
>> Bob Dunahugh
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>>
>
>
>
> --
> Bruce Hart
> 1976 Palm Beach
> Milliken, Co
> GMC=Got More Class
>
>


--
Bruce Hart
1976 Palm Beach
Milliken, Co
GMC=Got More Class
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Bruce Hart 1976 Palm Beach 1977 28' Kingsley La Grange, Wyoming

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Re: [GMCnet] Carburetor [message #314516 is a reply to message #314470] Sun, 12 March 2017 16:33 Go to previous message
BobDunahugh is currently offline  BobDunahugh   United States
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Registered: October 2010
Location: Cedar Rapids, IA
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Senior Member

Just checked the other carb on the 78 - 403. Same 17058559 carb. So this is the number for Dec of 77, and Jan of 78. Bob Dunahugh

________________________________
From: Bob Dunahugh
Sent: Saturday, March 11, 2017 11:42 PM
To: gmclist@list.gmcnet.org
Subject: RE: Carburetor


The carburetor in our 78 403 is 17058559. Sometimes carb numbers change during the year. This GMC was built in January of 78. Our other 78 403 GMC was built in December of 77. I believe there's 122 VIN's between them. I'll check the carb numbers on it tomorrow. Be interesting.

Bob Dunahugh
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