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GMC V6 and V12 Engines Engine repair and rebuilding

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  #1  
Old September 26th, 2015, 03:34 PM
Clarke Clarke is offline
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Default Carb leak - Stock Stromberg 23-133A

I've had a consistent gas leak in my carb since I've had this truck (6 or 7 years). I thought it might be leaking from the body joint/gasket towards the top part of the carb (sorry, not a carb guy, I don't know the proper terms), but the carb was rebuilt a year or two ago, it still leaks.

Recently, I have wiped the outside of the carb clean/dry and closely watched for the source of the leak(s). I'm fairly confident it's leaking from the two large silver colored screws on the front of the carb (lower area). Due to limited room, I used a penny to tighten them, but they were already tight and it still leaks the same. I have attached a photo...

The leak is not bad, but enough it drips occasionally and that makes me a little nervous.

What is the purpose of these screws? Can I take these out and apply some type of gas resistant sealer?

Curious to know if this is a common issue with this particular carb?


Thank you,

David
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  #2  
Old September 26th, 2015, 09:20 PM
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David R Leifheit David R Leifheit is offline
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Default Re: Carb leak - Stock Stromberg 23-133A

Quote:
Originally Posted by Clarke View Post
I've had a consistent gas leak in my carb since I've had this truck (6 or 7 years). I thought it might be leaking from the body joint/gasket towards the top part of the carb (sorry, not a carb guy, I don't know the proper terms), but the carb was rebuilt a year or two ago, it still leaks.

Recently, I have wiped the outside of the carb clean/dry and closely watched for the source of the leak(s). I'm fairly confident it's leaking from the two large silver colored screws on the front of the carb (lower area). Due to limited room, I used a penny to tighten them, but they were already tight and it still leaks the same. I have attached a photo...

The leak is not bad, but enough it drips occasionally and that makes me a little nervous.

What is the purpose of these screws? Can I take these out and apply some type of gas resistant sealer?

Curious to know if this is a common issue with this particular carb?


Thank you,

David
You can see the copper gasket around the edge of the screws in the picture, my guess is that the gasket wasn't replaced when the carb was rebuilt. I don't have a manual handy so I cannot tell you what they are for, but I can certainly tell you they shouldn't leak.
Did you rebuild the carb or did a shop do it?
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(2) 1961 1500
1962 1000
1963 2500
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1964 2500
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Old September 26th, 2015, 09:54 PM
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AZKen AZKen is offline
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Default Re: Carb leak - Stock Stromberg 23-133A

Do I see fuel above the screws? If so, gravity is telling you something unless there is updraft from fan or forward motion. Use only proper screw driver with wide blade that barley fits slot. A penny would have no torque to seal a copper gasket. If that's what is leaking.
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Old September 27th, 2015, 12:03 AM
Clarke Clarke is offline
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Default Re: Carb leak - Stock Stromberg 23-133A

I didn't rebuild it myself. I had it done when the Dyno guys were rejetting it. I bought two rebuild kits at the time. I'll look through the kit to see if there is something that looks correct.

I believe the gas above if from updraft. It's been months since I've cleaned the outside. The couple times I have cleaned it, it wet at the two screws and dry above. But after I drive it a while it gets wetter towards the top.
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Old September 27th, 2015, 12:48 AM
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AZKen AZKen is offline
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Default Re: Carb leak - Stock Stromberg 23-133A

Understood, probably updraft. The main jet plugs have copper ring gaskets as said. Don't know why new ones would leak. If they both leak. That means the same mistake, like wrong gasket, plug too tight, plug too loose; as opposed to a bad plug or threads. You WILL, of course, have to remove the carb and examine the cause. I think I would find new rings, try to find out how tight is tight, and replace. Examine the sealing face of plugs and sealing face of carb hole for burrs, nicks or worse. Examine how crushed the rings are. The carb is pretty easy to remove with minimal effort and a little spilled gas. Maybe these rings have a specific orientation, I.E. right way/wrong way against carb face.

Last edited by AZKen; September 27th, 2015 at 01:09 AM.
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Old September 27th, 2015, 05:10 AM
snazzypig snazzypig is offline
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Default Re: Carb leak - Stock Stromberg 23-133A

I believe the Strombergs are notorious for leaking at the main jet plugs. I recently bought an old stock WW rebuilt by a national rebuilder possibly 30 years ago and they had sealed the threads with some sort of clear epoxy. The nasty gas we're forced to use today will probably dissolve the epoxy sooner or later. I don't know of any chemical sealer that today's gas won't attack.

AZKen's advice is good. New copper sealing rings tightened well, with the sealing faces free from nicks or imperfections. I speak from experience. A few weeks ago I rebuilt a Stromberg and did see a small nick on one of the sealing faces of the carb. I securely tightened both plugs with new copper rings, hoping they both would seal. Wrong. When I placed the carb into service, the defective side immediately began to seep gas.

Also, the two small plugs at the front that look like little derbys could also be seeping.
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Old September 27th, 2015, 05:57 AM
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AZKen AZKen is offline
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Default Re: Carb leak - Stock Stromberg 23-133A

It is common to seal permanent plugs with JB Weld or equiv. These are usually cross drilled holes to connect to other holes. The passages could not be cast. I have sealed many carbs with JB Weld. Only on the permanent plugs. If those are leaking, consider that. Also keeping in mind what Snazzy said, I wonder if gas tank sealer will work. I have a hunch it's all the same epoxy. On the screw in, I don't advise using any sealer whatsoever. Just the rings. You can email to some carb companies that have online rebuilding videos and they may be kind enough to advise or sell you new copper seals.
1. Mike's Carburetors http://www.carburetor-parts.com/Copp...er_p_3285.html
2. The Carb Doctor
3. Carbking

Your Stromberg WW Part number is for 60-64 305 C, D, E, 351" ENG, A, B, E, K, L, S, V, 4000 & 5000 SERIES. Walker is a famous old carb parts co. Here is a site with some WW copper washers. Scroll down to about sheet 7 to find G45D and G45C, sold by ID/OD measurement. You will need to measure yours. I don't see how to order except to google their website/find distributors.
http://www.walkerproducts.com/wp-con...l/stromber.pdf
You will also see tons of WW little parts and even aluminum plugs and caps.

Last edited by AZKen; September 27th, 2015 at 06:51 AM.
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Old September 27th, 2015, 02:16 PM
Clarke Clarke is offline
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Default Re: Carb leak - Stock Stromberg 23-133A

Thanks guys! As usual, lots of good advice.

I've been putting this off long enough. I need to make it a priority and correct the issue.


Thanks again,

David
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