MudEye

My Cutlass has had a rich gas smell lately. Under the hood I've see lots of gas on the base of the Quadrajet. 4 barrel not working... Has been very stubborn at starting lately. And has embarrassed Me at several stops. Turning over and over and over it finally starts with my foot to the floor.... Runs extremely rough and dies if I let off the gas. I limp home and park. Suspicious of a possible head gasket?? I rent a compression tester. On one side I get 150 150 140 140.
The other side I get 100 125 110 120 Anyone share their wisdom here.....?

MDchanic

1. Your float is heavy or your needle valve is leaking.

2. Yes, you may have a head gasket leak, though it is unusual to have one on all cylinders in a bank - next, do a leakdown test.

You did do the tests on both sides with the throttle fully open, right?

- Eric

cjsdad

It sounds like you have at least two issues at the same time. The gas smell and leaking carburetor may be the reason for hard starting and rough running.

The low compression could be many different things. It could be a bad head gasket like you suggest but it seems unlikely that all four cylinders would go bad at the same time. Not impossible, just unlikely. Maybe it's time to try a leak-down test to see where you are losing your pressure, rings, valves, or gaskets.

MDchanic

That's because you are smart.

- Eric

MDchanic

Yes and Yes.


They do sell a kit, but the only extra thing that that does is to measure the amount of air that is leaking, which is not strictly necessary.

Your compression tester gauge may have an air fitting in its line, which you can attach to an air compressor, if not, you can easily buy one - you bring the cylinder to TDC compression stroke and pressurize it, usually with about 60psi (don't want to push the piston down), and then look and listen for the leak in the oil filler, the carburetor, the tailpipe, etc.

- Eric

Railguy

If the float is heavy it will start easyer when cold harder when warm. Did you have the air cleaner off could be a dirty air cleaner or a mouse nest. This wouldn't explain the compression test though .

Sugar Bear

Are the cylinder heads matched pairs? Was one head replaced with a different CC? Check the casting numbers.

don71

I might suggest tackle one monster before the other.

Rebuild the carb. Do the usual cleaning, replacing of gaskets, filter, and checking for proper choke operation. Carb kits are cheap. Keep an eye out for bad vacum hoses and loose connections.

A low compression reading can be checked again along with a leak down test later.

One system at a time. Just don't put the cart before the horse.

A head gasket leak would be the last thing I'd check for right now, unless you have some other symptoms not mentioned.

MudEye

Air cleaner is off...

MudEye

How can I tell which carb rebuild kit is the correct one.. In this case ..67 quadrajet..

MudEye

Original Engine

MDchanic

You order rebuild kits according to the number on the side of the carburetor.

- Eric

cjsdad

The carburetor number will be stamped into the driver's side of the carb body as seen in the picture. This one is not a '67! Write the number down and call your local parts store and ask them if they have a rebuild kit for it. They should, but it is always best to make sure. There will be an instruction sheet with the kit that shows where and how everything goes back together but in this digital age pictures as you take things apart will help immensely as you reassemble.

IMG_20141212_181744445_zps70149fcf.jpg

gs72

IMO you should verify base engine integrity before you spend anything on the carb. Re-run the compression (wet and dry) test using the recommendations mentioned above. Run a leak down test. It is possible that the carb running that rich has washed down the cylinders and the rings on that bank unseated. If everything checks out ok with base engine, then repair the carb.

GEARMAN69

The 67-68 quadrajet are the most susceptible and likely units to have leaky well plugs under the primary in the center body. It will cause tremendous flooding , richness and leaks from the base plate area. Upon teardown if they have not been cleaned and sealed with epoxy like JB Weld then the will need to be. It may have just flooded hard and need just a carb rework and some clean spark plugs.

MudEye

I could not find a stamp...I found :Rochester Quadrajet.. A sticker with (remanufacrtured) 10312g and the rest on the sticker was worn out.. On the flap it had 36020... I seen no stamp anywhere on the carb..??

MDchanic

Right on the ridge, driver's side, facing forward, reading vertically from top to bottom, exactly as shown in the picture.

A very early '65-'66 QJ will have the number on a small round tag riveted to the driver's side.

I've never seen one without a number.

- Eric

cjsdad

Close up.


IMG_20141212_181744445_zps70149fcf.jpg IDNumber_zpse8963ee6.jpg

MudEye

IEric... I've went out 3 times now to look for that stamp...Man I am 1 dummy cause I cant't find it! Ok... I'm looking at the engine now... I'm on the driver side, Facing forward..I go to the side ( driver ) I cleaned everything... I still cannot find a stamp!!! There is a remanufactured sticker ..Maybe I should pull it off??

MDchanic

The number is on the front-facing surface of the rib.
You look at it while looking toward the back of the car, standing beside the left front fender.

- Eric

Railguy

Are you sure it's a Quadrajet?
Railguy

MDchanic

An excellent thought, but:

- Eric

MudEye

O.k. I did find a small round tag on the drivers side with 1027056 so maybe mine is the earlier model? Because there is no stamp anywhere like the picture posted above.....

MDchanic

Photograph.

That number does not fit the pattern for QJ numbering, as far as I know (even if you replace the initial 1 with a 7).

- Eric

MudEye

MDchanic

7027036, date code F7.

Original carburetor for a 1967 Olds with a 330, except California with A.I.R., manufactured in June of 1967.

- Eric

MudEye

So I finally found it then professor? Great! Had You not mentioned " round stamp " I would still be looking..... So that is the secret number then for ordering new carb kit? You think local auto parts carry? Thanks. I wonder what years the round stamp was used as identity?.....

Octania

Round tag prior to 1968
straight stamp on the :eft Rear rail 1968-up

with a few exceptions such as service carbs

MDchanic

Just give the parts guy the number - the kits are fairly universal - they may have one in stock, or they may have to order it in within a day or two.

- Eric

MudEye

Question.. What if I poured some oil into the low reading cylinders..?
If the gas washed away the oil..... And redo the compression test on those cylinders. Just a curious thought...

cjsdad

That is the point of the (wet and dry) comment. Remove all spark plugs and test the compression as is (dry), and then squirt a small bit of oil onto the cylinders and repeat (wet). If the compression goes up dramatically you have ring sealing problems. It may very well be that running the engine with excessive fuel on one bank of cylinders washed the oil out of the rings on that side and that may explain the low compression numbers. Resolving the fuel issue and driving a bit with normal fuel may allow everything to normalize and restore compression without further intervention.

Railguy

It could be that at one time one of the heads was removed and a different thickness of gasket was used. Or a valve job was done on one head and ot the other. You never know on an engine /car this old.

Railguy

MudEye

Thanks all..Recap... bad compression on a couple cylinders ,rough running, heavy gas smell, stalling.... Did a wet compression test and compression shot up to normal-140-150.
Rebuilt carb,new plugs,replaced points and condenser. Fired up and runs great now....
Back to my everyday driver....Thanks to all..... One thing though.. Takes longer to start..And bogs down on acceleration...Other than that..The carb rebuild worked and
I'm driving everyday again....

MudEye

Thanks all..Recap... bad compression on a couple cylinders ,rough running, heavy gas smell, stalling.... Did a wet compression test and compression shot up to normal-140-150.
Rebuilt carb,new plugs,replaced points and condenser. Fired up and runs great now....
Back to my everyday driver....Thanks to all..... One thing though.. Takes longer to start..And bogs down on acceleration...Other than that..The carb rebuild worked and
I'm driving everyday again....

Fun71

That could something as simple as the secondary air door adjustment. It is fairly sensitive - as little as 1/8 turn of the set screw can make a huge difference in operation.

Could also be the accelerator pump. Hard to diagnose without more details on exactly what is happening.

MDchanic

So... What about the compression?

- Eric

MudEye

Compression on those 2 cylinders returned to normal after carb rebuild ( 140-150 )

Octania

That's one hell of a carb rebuild.

MDchanic

Wow.

- Eric

cjsdad

That could also be the timing is off after replacing the points and condenser. Did you set the timing before or after you set the dwell? Setting the dwell changes the timing so it needs to be done first. Just a thought.