trouble with 68 GMC 305 V6 - The 1947 - Present Chevrolet & GMC Truck Message Board Network

riley1952&1968 · 10-25-2006, 11:41 AM

I am having trouble with the carburetor flooding gas out the top and on to the manifold when the engine is warm. This occured after I had the carb rebuilt. We installed a fuel pressure regulator and this has not seemed to help. I have not been able to find a remanufactured fuel pump. If anyone has any suggestions or knows where I could find some original parts, I would greatly appreciate it. Thanks!

Aarons72s · 10-25-2006, 03:24 PM

Sounds like the float is sticking? That would be my guess.
Aaron

stllookn · 10-25-2006, 04:38 PM

Where is the gas leaking from? Who rebuilt the carb? An inexpensive rebuild will not include replacement of the throttle shaft bushings which can be worn and leak badly. What kind of carb is it? Check the float level and make sure they got the needle assy. seated and adjusted correctly.

motocrosschump · 10-25-2006, 05:32 PM

sound like a bad needle valve or seat, or improper float height.

Longhorn Man · 10-25-2006, 05:41 PM

any chance in a photo pointing out the location of the fuel?

riley1952&1968 · 10-25-2006, 06:23 PM

It is a stromberg ww, it was rebuilt by Joe's Carb(everybody says they are the best). Once the truck warms up and has been run for a little while the gas starts to pour out the top of the carb. I am going to get a rebuild kit from NAPA and see if anything changes. Any suggestions on how to tell if the needle assy. is seated and adjusted correctly? Thanks

Aarons72s · 10-25-2006, 06:37 PM

There should be a small paper gauge in the kit with instructions on how to set and check the settings.
Aaron

stllookn · 10-25-2006, 07:22 PM

Is Joe's Carb...local? I have never heard of them, but that does not mean squat! If he is local...give him a call and politely ask some questions. Most guys want another good reference and if they can help you you will certainly give them one.

Here is a link to The Carburetor Doctor and his GMC Stromberg WW carb manual.

http://www.tocmp.com/manuals/Carbs/Stromberg/index.htm

Check it out

Americanrider · 10-25-2006, 07:32 PM

Since you already have a fuel reg you can pull the stock pump fab up a blocking plate and go electric. Frame mounted under the cab near the tank with an in-line can filter. I'm doing that to all of my trucks. Every once in a while big V6's show up in the local wrecking yards down here.

CG · 10-25-2006, 10:17 PM

I have one of those Jimmy v6 in whats left of a 65 gmc 3/4 ton. I think the carb was rebuilt on it not long ago. Anyway it was a running driving truck before we canabalized it. I tried to give the engine away on this board for free...come and pull it...No takers.

JAKES 68GMC · 10-26-2006, 03:29 PM

My advice: put on a Holley 500 2bbl. and be happy.

10-25-2006, 11:41 AM	#1
riley1952&1968 Registered User Join Date: Oct 2006 Location: seattle Posts: 6	trouble with 68 GMC 305 V6 I am having trouble with the carburetor flooding gas out the top and on to the manifold when the engine is warm. This occured after I had the carb rebuilt. We installed a fuel pressure regulator and this has not seemed to help. I have not been able to find a remanufactured fuel pump. If anyone has any suggestions or knows where I could find some original parts, I would greatly appreciate it. Thanks!

10-25-2006, 03:24 PM	#2
Aarons72s Registered User Join Date: Apr 2006 Location: oklahoma Posts: 10,670	Re: trouble with 68 GMC 305 V6 Sounds like the float is sticking? That would be my guess. Aaron

10-25-2006, 04:38 PM	#3
stllookn Saving 1 truck at a time! Join Date: Aug 2001 Location: Kent, WA Posts: 6,465	Re: trouble with 68 GMC 305 V6 Where is the gas leaking from? Who rebuilt the carb? An inexpensive rebuild will not include replacement of the throttle shaft bushings which can be worn and leak badly. What kind of carb is it? Check the float level and make sure they got the needle assy. seated and adjusted correctly. __________________ '68 C20 Longhorn 50th Anniversary 400/TH400 '68 C20 Longhorn 50th Anniversary 468/TH400w/buckets '72 C20 Halfhorn (Longhorn w/o cab and front clip) '69 Flxible Cruiser (look up ugly in the dictionary)

10-25-2006, 05:32 PM	#4
motocrosschump Registered User Join Date: May 2005 Location: Texarkana, AR 71854 Posts: 397	Re: trouble with 68 GMC 305 V6 sound like a bad needle valve or seat, or improper float height. __________________ 2006 Titan SE Crew Cab Daily Driver 2005 Mazda Tribute (Wifes car) 1969 C10 SWB 350/3 Fleet "Max" 1969 Chevelle 2 door 350/3

10-25-2006, 05:41 PM	#5
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	Re: trouble with 68 GMC 305 V6 any chance in a photo pointing out the location of the fuel?

10-25-2006, 06:23 PM	#6
riley1952&1968 Registered User Join Date: Oct 2006 Location: seattle Posts: 6	Re: trouble with 68 GMC 305 V6 It is a stromberg ww, it was rebuilt by Joe's Carb(everybody says they are the best). Once the truck warms up and has been run for a little while the gas starts to pour out the top of the carb. I am going to get a rebuild kit from NAPA and see if anything changes. Any suggestions on how to tell if the needle assy. is seated and adjusted correctly? Thanks

10-25-2006, 06:37 PM	#7
Aarons72s Registered User Join Date: Apr 2006 Location: oklahoma Posts: 10,670	Re: trouble with 68 GMC 305 V6 There should be a small paper gauge in the kit with instructions on how to set and check the settings. Aaron

10-25-2006, 07:22 PM	#8
stllookn Saving 1 truck at a time! Join Date: Aug 2001 Location: Kent, WA Posts: 6,465	Re: trouble with 68 GMC 305 V6 Is Joe's Carb...local? I have never heard of them, but that does not mean squat! If he is local...give him a call and politely ask some questions. Most guys want another good reference and if they can help you you will certainly give them one. Here is a link to The Carburetor Doctor and his GMC Stromberg WW carb manual. http://www.tocmp.com/manuals/Carbs/Stromberg/index.htm Check it out __________________ '68 C20 Longhorn 50th Anniversary 400/TH400 '68 C20 Longhorn 50th Anniversary 468/TH400w/buckets '72 C20 Halfhorn (Longhorn w/o cab and front clip) '69 Flxible Cruiser (look up ugly in the dictionary)

10-25-2006, 07:32 PM	#9
Americanrider Registered User Join Date: Dec 2004 Location: NW, WA. Posts: 1,421	Re: trouble with 68 GMC 305 V6 Since you already have a fuel reg you can pull the stock pump fab up a blocking plate and go electric. Frame mounted under the cab near the tank with an in-line can filter. I'm doing that to all of my trucks. Every once in a while big V6's show up in the local wrecking yards down here.

10-25-2006, 10:17 PM	#10
CG BlahBlahBlah Join Date: Feb 2002 Location: Wa. Posts: 19,845	Re: trouble with 68 GMC 305 V6 I have one of those Jimmy v6 in whats left of a 65 gmc 3/4 ton. I think the carb was rebuilt on it not long ago. Anyway it was a running driving truck before we canabalized it. I tried to give the engine away on this board for free...come and pull it...No takers. Last edited by CG; 10-25-2006 at 10:18 PM. Reason: cause I cant spell for shoot =)

10-26-2006, 03:29 PM	#11
JAKES 68GMC Aluminum slot wheels rule... Join Date: Jan 2006 Location: Maine Posts: 6,212	Re: trouble with 68 GMC 305 V6 My advice: put on a Holley 500 2bbl. and be happy.



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