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Eman
12-03-2005, 09:56 PM
Okay, I just rebuilt the carburetor and put it back on last night. She doesn't want to die when pressing the accelerator now, but idle is rough and there is some sort of noise in or near the carburetor.

The hissing noise at idle sounds like a choky hissy gurgly noise. It's not continuous but at intervals. I cleaned AND soaked EVERYTHING... Blew out with carb cleaner and compressed air. The only thing I didn't take out were the two tubes, but remember shooting stuff through them with no problem.

It does run smoother at a higher idle. Tons. And although it is less shaky at the higher idle, I believe I can still hear that noise I mentioned above.

Any suggestions?



1951 Commander Starlight Coupe (aka "Stella")
www.bulletshots.net

Eman
12-03-2005, 10:33 PM
By the way, I haven't adjusted the two idle bleed air adjustment screws yet, which I assume will make a difference with the roughness, but the noise it's making still kinda scares me.

And just to make sure, I need to screw those in ALL the way, then back out 1-1/2 turns? (Not just until I meet some stiffness, then back out.)



1951 Commander Starlight Coupe (aka "Stella")
www.bulletshots.net

whacker
12-03-2005, 10:47 PM
It sounds to me like you didn't get a good seal when you remounted the carb. Start the engine and let it idle and warm up. Then use an unlit propane torch to release propane around the base of the carb where it bolts to the manifold. If the engine idle speeds up when the torch is by the base, you have a leak. I assume you used a new base gasket? You may have to use a liquid gasket sealer like permatex to get a good seal. If it is really bad, you may have to remove the manifold and have the top planed flat, but that would be really extreme.

Eman
12-03-2005, 10:59 PM
Thanks for responding, Whacker. I'll still try the torch, but I did use a new base gasket and sealer on the base of the carburetor. :(



1951 Commander Starlight Coupe (aka "Stella")
www.bulletshots.net

Tbatson
12-04-2005, 06:42 AM
I think you have checked for vacuum leaks in the normal places. Now take a look at the throttle body linkage. Wear would be expected on the shaft and the casting in the throttle body. The initial idle adjustment is in till they are firm and then out 1 1/2. Now adjust until the engine runs best.
Tom

Mike
12-04-2005, 08:04 AM
About the two "idle air bleed adjusting screws":
Generally, you bottom them out and back out 1 & 1/2 turns for an initial setting. The instructions that came with the carb kit, or the manual may specify different. It's just a place to start.
The screws are soft brass. You don't want to screw them down so tightly that you put a groove in them; or ream the hole in the carb. If the pointed end of the screws have a groove, they won't make a smooth change in the mixture, as you adjust them. There is no reason you couldn't use sand paper to reshape a damaged screw.
Fuel puddles in the intake manifold sometimes; making it difficult to detect a difference as these screws are adjusted, especially as you turn them in, (going leaner). You have to use up puddled fuel. Adjust slowly. Usually, you are supposed to turn the screws in till the engine gets slightly rougher; then out till it smooths.
Sears has a large, inexpensive vacuum gauge; that would give you a visual indication as you tune.
Since you can make the engine idle slowly, I doubt you have any serious vacuum leaks.
Enjoy tuning your carb!
Mike M.

Mike
12-04-2005, 08:22 AM
There's normally a lot of noise from the carb throat, while the engine is running.
I didn't mention that you will need to adjust the stop screw on the throttle linkage, to keep the idle near normal speed, as you adjust the mixture screws. At higher speeds the ignition advance comes in, and engine speed "takes off". You are also using different circuits in the carb.
Mike M.

Roscomacaw
12-04-2005, 05:40 PM
Mike, I've gone over all those points with Eric via E-mail. He was thinking that spark plug gap would give him fits if it wasn't spot on and I assured him that just wasn't so.;)

I've told him to play with those idle bleed air screws once he's run the engine up to full operating temp and the choke's fully open.
Eric's just a bit uncertain of himself since this is his first time under the hood to this degree![:I] (Don't mean to embarrass you Eric!)
Assuming he never removed the intake manifold, I'd have a hard time envisioning a vacuum leak at the carb base with a new base gasket - sealer or no!
I see either the bleed air screws grossly out of adjustment OR something askew in the carb's idle circuit.
This car shouldn't have power brakes and it doesn't have a vacuum modulator valve for it's tranny so I doubt there's a vacuum leak UNLESS someone had tinkered with the intake manifold and messed up the gaskets for it.[}:)]
Like any of these old Studes we get, you really DON'T know what's been done to it in the past and so we just assume it's in OK shape.

But Eric, try adjusting those screws in and out a bit once you've warmed it up and let's hear what difference, if any, it makes.;)

Miscreant at large.

1957 Transtar 1/2ton
1960 Larkvertible V8
1958 Provincial wagon
1953 Commander coupe
1957 President 2-dr
1955 President State
1951 Champion Biz cpe
1963 Daytona project FS

Eman
12-04-2005, 08:23 PM
I'll start with the screws as you guys suggested and not even pay attention to the noises yet. And don't worry, I think it's obvious with my questions that I'm no mechanic. But that's part of the reason I jumped in with both feet on this anyway. :D

Thanks for the info. I'll let y'all know how it goes.


1951 Commander Starlight Coupe (aka "Stella")
www.bulletshots.net

sasjdw
12-05-2005, 02:00 PM
I'm restoring my Speedster to (I hope) show condition and the Carburetor, while it works fine, is quite dirty and dull looking. Rather than simply rebuild it, I would like to have it rebuilt and refinished so that it looks new. Does anyone have any experience with a very reputable vendor that can restore the carb? Would anyone recommend one of the Stude vendors that sell 'rebuilt' carbs for the Speedster?

Thanks.

James D. Wilkerson

Roscomacaw
12-05-2005, 02:47 PM
Dave Thibeault - no question about it!;) (978)-897-3158

Miscreant at large.

1957 Transtar 1/2ton
1960 Larkvertible V8
1958 Provincial wagon
1953 Commander coupe
1957 President 2-dr
1955 President State
1951 Champion Biz cpe
1963 Daytona project FS