When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
My '66 Ninety Eight (original 425) has a stuck or jammed choke shut-off that's not fixable, my mechanic tells me. He's an 80-year-old carb expert, so knows his stuff.
He's got the whole thing apart and is about to do a rebuild with a carb kit. But he says that 'choke shut-off' part won't fully close the choke when starting and then won't release it at all upon running. So I'm over-fueling, with fuel spilling out of the carb. A fire hazard, no doubt.
He's called around, even drove to a farm to check on a few wrecks, but hasn't found anything usable. Any suggestions?
Just realized I spelled that wrong in the subject. Sorry about that. Can't seem to edit that.
Paul in Canada
Last edited by pfriesen; May 12, 2026 at 04:50 PM.
Reason: spelling
My '66 Ninety Eight (original 425) has a stuck or jammed choke shut-off that's not fixable, my mechanic tells me. He's an 80-year-old carb expert, so knows his stuff.
He's got the whole thing apart and is about to do a rebuild with a carb kit. But he says that 'choke shut-off' part won't fully close the choke when starting and then won't release it at all upon running. So I'm over-fueling, with fuel spilling out of the carb. A fire hazard, no doubt.
He's called around, even drove to a farm to check on a few wrecks, but hasn't found anything usable. Any suggestions?
Just realized I spelled that wrong in the subject. Sorry about that. Can't seem to edit that.
Paul in Canada
What carb is on this car? Is it just the thermostatic coil you're talking about? Fusick sells a reproduction model of the one for the Quadrajet.
“Fuel spilling out of the carb” doesn’t sound like a choke issue to me. If it’s an issue with the choke pull-off, that should be fairly easy to find parts to resolve the issue.
Sounds to me like we have failure to communicate ... do you think you could get your mechanic to post in this thread so he could explain the problem in more detail? Might be very helpful.
He's 80, lol. Don't think he does computers. I'll try to clarify:
There were other issues (gaskets) causing the fuel to spill out of the carb. He's addressing that with a rebuild kit.
But my choke flap, he says, never fully closed upon starting, and never fully opened when warmed up. So what he called the "choke shut-off" or "pull-off" is jammed and not operating properly. It's a part separate from the carb. I should have got a photo when I went to his garage today.
I do appreciate the quick responses. And it's a quadrajet. Model 7026250.
From the description the problem should be fixable with parts vs a carb replacement. Sounds like a choke thermostat housing, choke thermostat and/or a choke pull off maybe needed at most. Best case scenario would be if linkage wasn't positioned correctly.
Video of the problem may help particularly showing linkage on the passenger side of the carburetor in motion.
If it's only a choke pulloff replacement issue, you CAN basically temporarily tie the choke flap open until you can find the proper one. Will make cold starts a PITA for a bit, but once it's warmed up, it should do just fine. Since it's external, you should be able to rebuild the carb entirely and make it run better. You can deal with the choke pulloff later when you do find a suitable replacement. That's what I would do for now, but obviously continue the hunt.
He has identified the problem. It's not linkage. I guess my question is basically where on earth does one get this choke pull-off part?
I already told you. Fusick sells a reproduction of the one for the '66 quadrajet. This is the thermostatic choke coil, mounted separately on the intake manifold, and it is responsible for closing the choke flap when you hit the accelerator prior to cold start. The coil then heats up as the engine warms up, relaxes and assists with the gradual opening of the choke flap until fully warmed up.
There is also the vacuum break, which opens the choke slightly after the car starts up to prevent from completely choking the engine on startup and it's mounted on the choke assembly on the side of the carb. This part is 100% unique to the '65 and '66 Quadrajets and is not easily obtainable. It can be rebuilt, however. Quadrajetpower.com told me as long as I have the original metal section of the vacuum break, they can rebuild it for you. I've seen the odd one for sale on Ebay PN 7031101
Last edited by ourkid2000; May 13, 2026 at 05:36 AM.
No doubt 1965 & 1966 employed exceptionally unique Quadrajet carburetors. I'm not a Quadrajet expert - I've seen a fair share from this period (65/66) & I try to keep abreast following others w/ more knowledge. To that end, I've often wondered if there were two styles of the 7026250 carburetor? A big guess I know. Mike (Mike's Carburetor Parts and Fuel Injectors) lists the 7026250 (4MV) as fitting the 400 (only) and not the 425 (odd), and I place a good deal of trust in Mike's knowledge. Also, to be fair (I guess?) the 7026250 has a secondary dampener (not a true vacuum break), which preceded a true vacuum break (as we know it) used 1st in 1967 through 1989. I don't have enough knowledge of these two model year carburetors as others, but like ourkid2000 said 1965 & 1966 are truly unique carburetors.
Secondary dampener 1966 7026250 (stolen directly from Facebook)
Mike lists this choke pull-off as fitting the 400 cid but not the 425 cid. This is the same page the OP posted (earlier) when he entered his carburetor number (7026250); yet, note - Mike does not list the 425 cid (and, I trust Mike) - go figure.
Mike lists this choke pull-off as fitting the 400 cid but not the 425 cid. This is the same page the OP posted (earlier) when he entered his carburetor number (7026250); yet, note - Mike does not list the 425 cid (and, I trust Mike) - go figure.
Not sure where Mike's getting his info from and I'm not sure why you would use that as a reference anyway when the Delco manual tells you what you need to know from the official source. Norm, you'd absolutely be the first one to give me **** about doing something like that. Anyway, there was two versions of the 7026250 and I have both sitting here on my bench. The only difference between them was the throttle linkage which is swappable depending on the car it was going on. Toronado got a specific one, the rest got the other. Again, I have both here.
So, here it is......everything you need (including which engines it was used on). Pay particular attention to the dates on this publication as well:
Last edited by ourkid2000; May 13, 2026 at 03:42 PM.
Not sure where Mike's getting his info from and I'm not sure why you would use that as a reference anyway when the Delco manual tells you what you need to know from the official source. Norm, you'd absolutely be the first one to give me **** about doing something like that. Anyway, there was two versions of the 7026250 and I have both sitting here on my bench. The only difference between them was the throttle linkage which is swappable depending on the car it was going on. Toronado got a specific one, the rest got the other. Again, I have both here.
So, here it is......everything you need (including which engines it was used on). Pay particular attention to the dates on this publication as well:
Those are excellent images. Thanks for posting those. I enjoy learning.
Did you and Dale go to the exact same Finishing School?
Norm, you'd absolutely be the first one to give me **** about doing something like that.
Additionally, I have no idea what you even mean by me giving you ****. Sorry you take offense to normal discourse in communicating. Wait a minute, no I'm not....
Oh I don't take offense at all Norm......i'm just giving you some good natured ribbing. If I had posted spurious internet data, even if it is from a well respected fellow like our man Mike here, you'd be all over me for "believing everything I read on the interwebs" and pointing me to an offical source such as a Delco manual or a CSM within a minute. I've learned many a lesson on here from knowledgeable fellers, such as yourself, that if I'm gonna post something like that I better have my ducks in a row because I'm getting called on it. You guys have forgotten more about Oldsmobiles than I'll ever know but when it comes to 1966 Oldsmobile Quadrajets, I know my stuff. However, I have no idea who Dale is.
I'll show it to my guy and proceed. It sure looks right. Hope it's a match.
Thank you.
You've ordered the wrong part. See my parts catalog above. Item #32, Vacuum Break control assembly. PN 7031101. Mike's carb parts website has it listed under PN P7133 and it's a "send your old one in and he rebuilds it" only type thing as they are not reproduced anymore.
Last edited by ourkid2000; May 13, 2026 at 05:00 PM.
Oh I don't take offense at all Norm......i'm just giving you some good natured ribbing. If I had posted spurious internet data, even if it is from a well respected fellow like our man Mike here, you'd be all over me for "believing everything I read on the interwebs" and pointing me to an offical source such as a Delco manual or a CSM within a minute. I've learned many a lesson on here from knowledgeable fellers, such as yourself, that if I'm gonna post something like that I better have my ducks in a row because I'm getting called on it. You guys have forgotten more about Oldsmobiles than I'll ever know but when it comes to 1966 Oldsmobile Quadrajets, I know my stuff. However, I have no idea who Dale is.
That's cool. I thought I had offended you & trust me it was never my intention to offend your knowledge and give you $hit...cause I'm aware you know your stuff. Have a great day.
That's cool. I thought I had offended you & trust me it was never my intention to offend your knowledge and give you $hit...cause I'm aware you know your stuff. Have a great day.
Norm's the kinda guy on this site that I'd love to have a beer with!
You've ordered the wrong part. See my parts catalog above. Item #32, Vacuum Break control assembly. PN 7031101. Mike's carb parts website has it listed under PN P7133 and it's a "send your old one in and he rebuilds it" only type thing as they are not reproduced anymore.
This guy has one for sale. Wants serious money + shipping, but when you look at the photo it looks pristine. I agree Delco NOS is the best stuff. Sometimes, I'm a little nervous about parts w/ a diaphragm after years of storage.
You've ordered the wrong part. See my parts catalog above. Item #32, Vacuum Break control assembly. PN 7031101. Mike's carb parts website has it listed under PN P7133 and it's a "send your old one in and he rebuilds it" only type thing as they are not reproduced anymore.
I didn't order that part. Turns out my mechanic says he only needs the one you describe above: the vacuum break (7031101). Found it on ebay at the link below. Just ordered it. Fingers crossed. And thank you.
This guy has one for sale. Wants serious money + shipping, but when you look at the photo it looks pristine. I agree Delco NOS is the best stuff. Sometimes, I'm a little nervous about parts w/ a diaphragm after years of storage.
Damn, should have looked at these other replies first. Agree, Vintage Chief, that does look pristine. I bit the bullet. Ordered that one, too. If I can't cancel the first one, I guess I'll have an extra.
Damn, should have looked at these other replies first. Agree, Vintage Chief, that does look pristine. I bit the bullet. Ordered that one, too. If I can't cancel the first one, I guess I'll have an extra.
If you ever get a chance, I'd love to see a few pictures of that carb on your car. I've yet to see a 7026250 on anything other than a '66 Toronado. I was beginning to think that they were never installed on other vehicles. People must have gotten tired of the inherent problems and just swapped them out over the years for something else because you just never see '66 Quadrajets in the wild on anything other than '66 Toros.
I'd be happy to provide that photo, kid2000. Should be getting the Olds back from my mechanic any day. He's doing a couple other things, too, including installing an electronic ignition.
And by the way, I was able to cancel my initial order of that aftermarket choke-pull-off. The minty-looking NOS one is on its way. Here's hoping it works.
If you ever get a chance, I'd love to see a few pictures of that carb on your car. I've yet to see a 7026250 on anything other than a '66 Toronado. I was beginning to think that they were never installed on other vehicles. People must have gotten tired of the inherent problems and just swapped them out over the years for something else because you just never see '66 Quadrajets in the wild on anything other than '66 Toros.
Sorry for the delay. Here are two photos of the carb on my '66 Ninety Eight. The work is done and it's running great.
Sorry for the delay. Here are two photos of the carb on my '66 Ninety Eight. The work is done and it's running great.
Well would you look at that! They do exist! This seems to be an incredibly rare find and thanks so much for these pictures. If you ever get a chance, I'd love to see a pic of the area around the throttle linkage at the carb......can't quite see the throttle arm too well in that first pic. Anyways, thanks again!
Well would you look at that! They do exist! This seems to be an incredibly rare find and thanks so much for these pictures. If you ever get a chance, I'd love to see a pic of the area around the throttle linkage at the carb......can't quite see the throttle arm too well in that first pic. Anyways, thanks again!
Be happy to. Gotta get some work done, hopefully get to it later today.
Here you go. Does this show what you wanted to see?
Hey just curious. That round PN medallion on the carb. What color would you say it is and what shape is the hole punched in the middle of it? They came in two colors in that year, orange and white. There was also two style holes punched it them.......round hole and rectangular.
These details differentiated between California and 49 state versions of the engines.
Last edited by ourkid2000; Jun 5, 2026 at 11:46 AM.
Hey just curious. That round PN medallion on the carb. What color would you say it is and what shape is the hole punched in the middle of it? They came in two colors in that year, orange and white. There was also two style holes punched it them.......round hole and rectangular.
These details differentiated between California and 49 state versions of the engines.
Looks like mine's the light color and the hole is round.
