Carburetor Issues on 71 GS 455

This is correct 71 455 carb I have. It’s an original Stage-1 carb. These are the vacuum ports you would have on a correct 71 carb.

 

Dave did she buy it? Man you must have regrets. I would miss that car. And i’m sure where live the streets are clean.

 

Ok now I am confused. You have the correct 71 carb you just got back you are using? Then that does have the low port for the canister hose. 71 Carb should be part# 7041540 if Automatic car. It would have had 73 jets and 44B primary rods. The 4 speed carb was 7041243 which had 73 jets and 45B metering rods. With those big 71 carbs you should never use any leaner. Secondary rods were AS in auto and AY manual.

 

Your having trouble with idle.... First thing to check is nozzle drip.. I guaranty it has it... second check your base gasket that yellow belly coward kept senting me the base gaskets for a 350 chevy 750cfm style carb NOT the buick 800 cfm.. The leak will be where the driver is pointing.

 

Appreciate your time and comments. Yes, my newly rebuilt carb is a 7041540. It has the port for the canister. Tonight I took the canister out and capped the port on the carb. I was able to get the car to idle. I tried connecting a vacuum gauge where the climate control vacuum can attaches to the manifold, but the vacuum was bouncing all over the place there. Tomorrow, I will try somewhere closer to the carb so I am not just on a single cylinder. If I cannot get it to steady, I will likely have to dig into the motor, but will wait until next fall. Back to the fuel canister, I pulled the fiberglass filter from the bottom and the one I picked up at a swap meet appears to have a fiber media in it. It does not have charcoal like the original. Not sure what the issue is, but with it connected, the car acted like it had a huge vacuum leak which it did. Back at it tomorrow and if it is nice enough I will try and drive it.

Thanks again

 

Will do. That may be what is causing the throttle to hang up a little bit before it goes back to idle. I have the gasket from the old carb, so will use that if I need to. Had the small vacuum device on the carb come apart when I was fiddling with things. Ended up putting the one on from the old carb. I have sent QJP and e-mail and asked for a replacement. Hopefully I will get a response.

 

I do not believe the old gasket will work. Your local NAPA should have one 4$

7041540. is that a California P#. all my 800 cfms are 704(20r3)240

 

this is a pic of a 800 cfm base gasket.

 

Quick, there are no California carbs on Buick’s of that era. That’s the standard 455 carb for an Automatic in 71. I posted all the part numbers above. Nothing for California only. The 4th digit in the part number is the year. All of your 7042 Or 3 part number carbs are from 1972 and 73. His is a 71.

 

Let me reword it a bit
OP carburetor is a last 3 digits are 540
I don’t what to be giving bad info on the gasket. My carburetors are 240 last 3 digits

 

A couple more things to try. Just completely forget about the charcoal can unless you absolutely insist on stock concourse look. It’s just not necessary. I would put the vacuum gauge directly on a port of the carb. One is full time vacuum. I forget which. You should have steady vacuum around 20 if I remember correctly unless you have radical can. And more about the charcoal can. Yes originals had charcoal inside and also a fiberglass filter in bottom. The replacement filters for those now are a white plastic media. Many bad canisters at this point have the charcoal falling out the bottom so those are trash. You say the extra you have has plastic media inside it? I have never seen those? Does it carry the same part number on top? Does it have just two ports or 3? Yours should have two. If you really need a good one post an ad with the part number from the original. There were literally millions of them made.

 

He needs gaskets specific for his carb. The 4th digit for year is huge. There are differences between 71 and the 72 carbs. Don’t get hung up on the last three digits of your carbs. You have to know year. They changed numbers every year so don’t try and make sense of it. They don’t match up year to year. I have 71 and 72 carbs and the baseplates are different. 72 has 1 less port on the baseplate. The gasket could be the same but might be different too. I would suggest contacting www.quadrajetparts.com tell them the part number and they will get you correct part. They have every part including that vacuum break that broke. Owner Greg Gessler is a Buick guy that previously ported heads. Top notch.

 

We built a 7041540 for his 71, and supplied the correct gasket. He emailed for a replacement vacuum pull off and it has already shipped. He had some questions about fast idle adjustment and we supplied information from that.
It does sound like vacuum connections have been an issue and many of you helped him with that.

Bob, last message I received from you indicated all was good. Sorry you hate us so much. We tried. We are a Quadrajet company, it is all we do now. And true, sometimes trying to save a 50 year old abused part and bring it back to perfect isn't possible. We are very thankful for the thousands of customers that we are able to take care of each year.

 

I found some more information on the California carbs. Apparently the fifth digit being a 5 means the carb is certified for California but in this case it was used for all 50 states not just Cal. 4 can also be used for that digit for Cal.