350-4 not running right

oldbird

New member
7
0
1
Buick Ownership
1968 buick skylark
New here so not sure if this is the right forum. In 1972 my wife bought a 1968 skylark and thirty years ago we put it in storage. It started right up (amazing) and ran great. Did some maintenance on it and the normal stuff. The fuel gauge was stuck on full so I dropped the tank and replaced the sending unit. That works now but the motor has an occasional miss at idle and coughs and dies when giving it throttle. So of course I thought it was the sending unit so pulled the two gas lines and put them in a bucket of gas. Same thing so then I blew out all the lines and put in a new filter. Same thing so now I checked dwell, timing, vac lines, spark plug wiring, etc. I just don't understand how it could go from kicking butt to running like crap just changing the fuel tank sending unit? Any ideas? Thanks, Glenn
 

2007LucerneCXL

Full Member
5,405
1,733
113
Illinois
Buick Ownership
2007 Lucerne CXL. and 1995 Lesabre currently, past 1973 Riviera, 1968 Riviera
A few things to consider is that the new gasoline "doesn't play well with others" on older vehicles so could be other rubber components that may have failed or are failing. Other items may be age related, carburetor, fuel pump etc if original may be something that could need replacement or rebuilding and not knowing what has been done or service history it's just a observation where else to look.
 

oldbird

New member
7
0
1
Buick Ownership
1968 buick skylark
It didn't have hardly any gas in it when I first started it. I put in a five gallon can of the 'modern' stuff and ran it a mile or two up and down the road a few times and it ran great. I also was surprised at how clean the tank was inside and after the new sending unit was put in I added what I thought would be a total of ten gallons to see if the gauge would read about half, it did. I was thinking about putting a new fuel pump on it just for the heck of it but just loosening the filter and starting it gas was pouring out when running.

I did some research on carb's and can't figure out which one I have, rodchester I think? I was looking at the carb and can't see any ID on it. I wanted to order a rebuild kit but don't know which one to order. Thanks for your help!
 
Last edited:

oldbird

New member
7
0
1
Buick Ownership
1968 buick skylark
A few facts: 1968 Buick Skylark 350-4, 98K miles, two door, GS California trim, all original with normal rust but not to bad.

Is there a place to run the VIN or maybe a way to identify the carburetor? Thanks
______________________________
 

oldbird

New member
7
0
1
Buick Ownership
1968 buick skylark
Thanks guys a lot, those will help me figure it out once I scrape the crud off to find the numbers. I have the front fuel feed line so that narrows it down. Just curious, do you guys think its probably a carb problem? I checked the timing with vac line disconnected and it was TDC like the book calls for. Also, the dwell was 30° and the old Sears dwell meter said the points were OK. Vac lines all looked OK as well as everything else.

I did try to join V8buick but after filling out the sign up form five times and it being rejected I gave up! I have no idea why the form was being rejected and also couldn't figure out who to contact about the problem. That's why I'm picking on you guys, lol.
 

MelsRegal

Full Member
Staff member
5,605
893
113
Buick Ownership
Regal GS 2017
Using an ohmmeter check each plug wire. The standard is no more than 1k per foot of wire.
______________________________
 

LARRY70GS

Full Member
2,547
219
63
Oakland Gardens, N.Y.
Buick Ownership
98 Riviera, 70 GS455 Stg1
Thanks guys a lot, those will help me figure it out once I scrape the crud off to find the numbers. I have the front fuel feed line so that narrows it down. Just curious, do you guys think its probably a carb problem? I checked the timing with vac line disconnected and it was TDC like the book calls for. Also, the dwell was 30° and the old Sears dwell meter said the points were OK. Vac lines all looked OK as well as everything else.

I did try to join V8buick but after filling out the sign up form five times and it being rejected I gave up! I have no idea why the form was being rejected and also couldn't figure out who to contact about the problem. That's why I'm picking on you guys, lol.

I can tell you that your carburetor probably needs to be rebuilt at this point. The ethanol in the fuel will quickly swell the accelerator pump rubber, and possibly the rubber tip of the needle seat assembly. Fortunately, it is very easy to get a rebuild kit that has the good ethanol resistant parts. This is likely the kit you need,

Quadrajet Rebuild Kit, GM 1966-74 4001B

Definitely get the part number of the quadrajet. It is stamped into the main casting right behind the throttle cable attachment. If the carburetor is still original, it should be part number 7029244.
QuadrajetPartNumber.JPG
Your problem may in fact be the accelerator pump failing. You can buy just that, but I think after 30 years, the carburetor really should be gone through.

Next time you put a timing light on it, check that the vacuum advance unit is actually functioning. They can deteriorate and leak, and not work. That will make a big difference in the way the engine runs, the fuel economy, and engine coolant temperature. I always make sure to run the VA off of manifold vacuum so it is available at idle. It makes a big difference.

I also encourage you to stay with V8buick. Most problems occur from the the activation e mail being sent to your spam folder. I can help you get registered there. You can e mail me at Larrymta@verizon.net, give me the screen name you are trying to use, and I will contact the administrator to get you set up. I have done this several times for others on this site.
 

oldbird

New member
7
0
1
Buick Ownership
1968 buick skylark
Good info Larry, Thanks! I googled V8buick and got a some contact info so will see what happens.
 

2007LucerneCXL

Full Member
5,405
1,733
113
Illinois
Buick Ownership
2007 Lucerne CXL. and 1995 Lesabre currently, past 1973 Riviera, 1968 Riviera
Just tossing in additional info to check on the distributor is to look at the spark advance weights and they moving freely. Again it's sounding like Larry70GS is the way to go on the carburetor and to be honest it's going to be something that will be needed. Tossing the coil and other aging items it may seem like a loosing battle, but I know of folks who did the piece meal approach which unfortunately meant they were constantly working on the next challenge LOL.
______________________________
 

LARRY70GS

Full Member
2,547
219
63
Oakland Gardens, N.Y.
Buick Ownership
98 Riviera, 70 GS455 Stg1
Good info Larry, Thanks! I googled V8buick and got a some contact info so will see what happens.

You're welcome. The owner and administrator of the board is Jim Weise. Let me know if you need help registering. Jim built my engine in my GS. I can easily get in touch with him to assist you in registering. For your car, there is no better bulletin board than V8buick.
 

oldbird

New member
7
0
1
Buick Ownership
1968 buick skylark
Just tossing in additional info to check on the distributor is to look at the spark advance weights and they moving freely. Again it's sounding like Larry70GS is the way to go on the carburetor and to be honest it's going to be something that will be needed. Tossing the coil and other aging items it may seem like a loosing battle, but I know of folks who did the piece meal approach which unfortunately meant they were constantly working on the next challenge LOL.

The weights are free. I searched a little bit last night to see if there is a 'tune up kit' instead of buying all that stuff separate.

You're welcome. The owner and administrator of the board is Jim Weise. Let me know if you need help registering. Jim built my engine in my GS. I can easily get in touch with him to assist you in registering. For your car, there is no better bulletin board than V8buick.

I'll let you know if I wasn't successful in getting a hold of Jim, I appreciate you offering help! Sounds like a good forum.
 

LARRY70GS

Full Member
2,547
219
63
Oakland Gardens, N.Y.
Buick Ownership
98 Riviera, 70 GS455 Stg1
Get your turbo buick badge right here!
Top