I've got a 51 S88 with a 52-53 intake/carb/and heads. The carb numbers show it being for a 58 348 Chebby. I'm having a hard time getting it to run. It has what seems to be a bad vacuum leak. I've found the carb to manifold and the bottom carb to throttle butterflies gaskets bad. I replaced them and it is still bad. The choke has to be almost completely closed (between 1/8 to 3/16 open) for it to run. I've sprayed carb cleaner just about everywhere possible and no difference. With the choke almost closed I get about 18-19" vacuum. When I open the choke it goes to the LOW single digits then dies even while it is on the high idle cam. It has a dual action fuel pump and I have the vacuum side disconnected and that's where I have my vacuum gauge. It comes right from the bottom of the carb. I also had the vacuum advance disconnected and plugged the carb opening thinking maybe the diaphragm was bad, no luck. I hooked it back up. There is no other ports or openings from the carb. When I had the carb off I did a visual check for cracks or anything strange and found nothing.

Without pulling the timing chain cover I checked the valve timing (#1 TDC, both valves closed, right on the timing mark. Thought that might be part of it. No luck.

Could I just have a bad carb?

The man that owned this car passed away and I bought it from the executor of his estate so I have nobody to ask what he did. The car was in a trailer for a long time. The fuel tank was bad and so was the fuel pump. I rebuilt the pump and have it running off of a gas can sitting in front of the radiator.

Any and all suggestions more than welcome.

 

Was the line to the distributor hooked to manifold vacuum?

 

yes

 

You need to connect that back, it will run like KAKA with it disconnected because your timing is way declined.

 

did that and still kaka

 

Have you tried spraying starting fluid (ether) around the intake, base of carb, etc...?

 

starting fluid, no carb cleaner,yes. That's how I found the bad carb gaskets and replaced them. Still no good. I sprayed everything from the front of the manifold to the back and no change in the engine.

 

The description sounds like restricted idle passages in the carburetor. The carb probably needs an overhaul. Closing the choke plate richens the mixture enough to make it run well and increase the vacuum.

If you take it apart, save all of the old gaskets and compare them to the new ones to make sure they match exactly by holding them together and checking both sides for correctness.

 

Well I'm back. I sent the carb out and replaced it with a correct 52 rebuilt carb and I still have the same problem. Still won't idle and runs like it has a bad vacuum leak. It runs, like I said before, with the choke almost completely closed and even if it is on high idle cam and I open the choke it stumbles and dies. I also rebuilt the fuel pump.
Ive got fairly good compression 120# on 6 cyl. and 100 on 2 others. The 2 low ones come up when I give them a shot of oil. I've checked the vacuum advance unit with a mighty vac unit and it holds a vacuum so that should be good. I've sprayed carb cleaner everywhere and it makes no difference. I've disconnected and plugged the line from the carb to the vacuum side of the fuel pump and it still dies. It's running off of gas in a can sitting in front of the radiator cause I didn't get the tank back from the radiator shop yet.

Any suggestions would really be appreciated.

 

Well I changed the intake gaskets just for giggles and grins and it didn't help BUT now when I shut the engine off after about 2-3-minutes I have about 1/4" puddle of gas in the intake. Called the carb guy and told him my problems and I'm shipping him back the carb for him to go thru again. He said it ran fine on his test car (54 Olds) but I am rather doubtful about that.

 

Well I finally got my carb from the rebuilder! He sent me a different one. At least it looks like it was rebuilt. The engine idles but has an off idle stumble, sometimes backfire. Great right? One of the idle mixture screws has no affect on the idle. I can screw it down tight and the engine keeps the same rpm.

I have 2 questions, 1. I get 8" of vacuum at the choke housing where the 1/4" tube hooks up from the intake? Is that right? I figure there has to be some vacuum to pull the heated air from the intake but that seems like a lot.

And #2 Can I get a recommendation for a real carb rebuilder.

 

Is you idle set pretty high? Can you lower it a bit to see if you can get the A/F mixture screws to work. Also if you look down into the carb is it dribbling fuel when it's running?

 

No, just the opposite -the idle is low. When I put the carb on and fired it up the idle set screw wasn't even hitting the stop. It idles at about 500 maybe 600 in neutral. that's a guess cause I dropped my tach/dwell meter and it didn't like that so now it refuses to work. I keep a 16 pound sledge hammer in the corner for stress relief purposes and it managed to meet my meter and now it really don't work.
I'll have to look tomorrow to check on the fuel dribble thing.

 

Why can't these problems be easy, huh? Sounds like the carb is still messed up. What carb are you running?

 

it's just a stock Rochester 4 barrel square bore from a 52 Olds. Nothing fancy. it's really a pretty basic carb.
What about that vacuum at the choke control housing?

 

Why not get a kit yourself and go through it. Sounds like there is something in the idle passage not allowing it to draw fuel. If you sprayed carb cleaner all over and did not notice any leaks, that's what I would do.

 

That's exactly what I'm going to do. My winter project. I've had it with this "rebuilder". Yes I did the carb cleaner spray to check for leaks and found nothing.

Thanks