Carburetor replacement?
#1
Carburetor replacement?
New to the site and classic Oldsmobiles.
I just bought a 1969 98 and has what appears to be the original Rochester quadra jet.
It's been messed with and not sure how well it is working and I'd like to replace it. Any opinions on a good replacement carb?
I just bought a 1969 98 and has what appears to be the original Rochester quadra jet.
It's been messed with and not sure how well it is working and I'd like to replace it. Any opinions on a good replacement carb?
#3
Post the model # of the Rochester Quadrajet. It may or it may not be the correct carburetor for your car. IOW, a PO may have made a swamp w/ carburetor not appropriately designed for your vehicle. The model # is located on driver side towards back of carburetor. Post that model #.
Quadrajet carbs were excellent carbs during that era. They make rebuild kits ($50 - $85), often times a simple rebuild kit (which you can do yourself) is all that's needed.
Quadrajet carbs were excellent carbs during that era. They make rebuild kits ($50 - $85), often times a simple rebuild kit (which you can do yourself) is all that's needed.
#4
Thanks. Will do.
it has definitely been altered by the PO. The choke doesn't close, he had it locked in the open position, and I'm not even sure the secondaries are working. It been tampered with bit not sure why.
If it does need replacement, is it best to find another quadra jet? Or are there other replacements that are recommended..
it has definitely been altered by the PO. The choke doesn't close, he had it locked in the open position, and I'm not even sure the secondaries are working. It been tampered with bit not sure why.
If it does need replacement, is it best to find another quadra jet? Or are there other replacements that are recommended..
#6
Rochester Quadrajet carbs were designed for both specific model years & specific engines. Aside from various linkages (which can appear & are often not too dissimilar), the idle circuit (which is NOT specific to engine RPM at idle), is active throughout the range of operation i.e. idle, acceleration, cruise & WOT. Albeit, your best choice is a Quadrajet Model # designed for your vehicle.
#9
A guy named Cliff Ruggles ( USED TO HANG OUT ON THE FORUM "CLASSICAL PONTIACS". He rebuilds them and tunes them to perfection. when I had mine done it cost me $225 + ship. Better if you DON'T BUY one of the "Generic" rebuilds !
#10
Cliff has retired from building carbs, but he still sells parts. There are several Q-Jet specialists on Facebook that do custom builds.
My vote is for the Q-Jet. Either rebuild yours with the proper parts, or buy one already built and calibrated for your application.
My vote is for the Q-Jet. Either rebuild yours with the proper parts, or buy one already built and calibrated for your application.
#12
#14
#17
Thanks for all the feedback everybody. Here are a couple pictures of the carb. I just purchased the vehicle and this is how the carb was when I got it. It does idle well runs well does not start without starting fluid.
I am not exactly sure what that screw is doing by the vacuum diaphragm. I definitely could use some guidance here thank you
I am not exactly sure what that screw is doing by the vacuum diaphragm. I definitely could use some guidance here thank you
#20
If you are talking about the screw in the last photo, what does that have to do with the choke? This is a divorced choke, which is in a pocket in the intake crossover. You are correct about the inlet repair. This is unfortunately all too common. A helicoil repair allows you to use the OEM inlet fitting and lose the adapters.
#22
The vacuum hose to the front vacuum break may be too long and restricting vacuum to the diaphragm. I would shorten the hose and check diaphragm operation. Next up is to remove that bolt that is jammed into the fast idle cam. Then check fast idle cam and choke operation and perform tune up adjustments - point dwell (if using points, use dwell meter), ignition timing-use timing light, idle mixture-use vacuum gauge, fast idle then curb idle speeds-use tachometer.
Can you post a picture of the right (passenger) side of the carburetor? I'd like to see the choke assembly.
Can you post a picture of the right (passenger) side of the carburetor? I'd like to see the choke assembly.
#23
...remove that bolt that is jammed into the fast idle cam. Then check fast idle cam and choke operation
#26
Post the model # of the Rochester Quadrajet. It may or it may not be the correct carburetor for your car. IOW, a PO may have made a swamp w/ carburetor not appropriately designed for your vehicle. The model # is located on driver side towards back of carburetor. Post that model #.
Quadrajet carbs were excellent carbs during that era. They make rebuild kits ($50 - $85), often times a simple rebuild kit (which you can do yourself) is all that's needed.
Quadrajet carbs were excellent carbs during that era. They make rebuild kits ($50 - $85), often times a simple rebuild kit (which you can do yourself) is all that's needed.
#28
I can't help but feel some basic restoration of the choke system will restore proper cold engine starting and operation.
The evil that some people do to a carburetor should be illegal. If that carb was a animal someone would be in jail.
#30
Exactly Norm. Without me under the hood I'm guessing that the choke pull off function of the front diaphragm is inoperative. I also suspect a weak choke thermostat, disconnected, or damaged choke linkage issue.
I can't help but feel some basic restoration of the choke system will restore proper cold engine starting and operation.
The evil that some people do to a carburetor should be illegal. If that carb was a animal someone would be in jail.
I can't help but feel some basic restoration of the choke system will restore proper cold engine starting and operation.
The evil that some people do to a carburetor should be illegal. If that carb was a animal someone would be in jail.
#31
If you are talking about the screw in the last photo, what does that have to do with the choke? This is a divorced choke, which is in a pocket in the intake crossover. You are correct about the inlet repair. This is unfortunately all too common. A helicoil repair allows you to use the OEM inlet fitting and lose the adapters.
Could be our one day to have fun w/ Joe (maybe). Now get off the lawn you kids.
#32
I've done a few myself but for the last one I used John Herald Jr. to rebuild it. It needed shaft bushings and he has the stuff to do that. I'm very happy with it.
Last edited by allyolds68; November 30th, 2023 at 05:00 AM.
#33
As mentioned above, Cliff isn't rebuilding carbs anymore however he offers the best rebuild kits out there.
I've done a few myself but for the last one I used John Herald Jr. to rebuild it. It needed shaft bushings and he has the stuff to do that. I'm very happy with it.
I've done a few myself but for the last one I used John Herald Jr. to rebuild it. It needed shaft bushings and he has the stuff to do that. I'm very happy with it.
#35
#36
Presumably to wedge the choke open due to the non-working coil