1955 Buick roadmaster engine cuts out while driving.

[Guest johnjackson]

Hey everyone. I have an issue I could use some help with. To start I just did a full rebuild on my carter 4 barrel and full tune up...plugs, wires, cap rotor, points, condenser, fuel filter, oil, oil filter and trans fluid and filter. My car idles great and smooth even when I put it into gear. Once I start going to try and go down the road it spits and sputters and sometimes will even cut out at 1/4 or so throttle for example trying to cruise at 30mph it will die out unless I flutter the heck out of the pedal and in the upper speeds it feels like it's miss firing. Possible vacuum advance? Any help would be great. It's a 1955 with a 322 and Dynaflow.

[JACK M]

fuel supply. Take a look at your filters and fuel lines.

[vermontboy]

My guess would be the carburetor - if it was me I would pull it and go back through all of the adjustments again. Before doing that make sure that there is nothing blocking the airflow (I found a mechanics rag in the airhorn on my 64 Chrysler once).

 

If you installed a new condenser try putting the old one back in place (QC on the new ones is non-existent).

 

Vacuum advance usually just reduces power but it only takes a minute to check with a timing light.

 

Just my guesses

[Guest johnjackson]

I greatly appreciate that. I most definitely. Also found my generator has also died out today so that will be getting rebuilt.

[uh6077]

Float adjustment maybe? Sounds like it isn't getting enough fuel. Doesn't take much fuel to idle or even rev up when not under a load. Either carb adjustment or maybe a clogged fuel filter?

[Rusty_OToole]

Spitting and sputtering usually means a fuel starvation problem. Check your fuel filters and fuel pump. Could also be an air leak in the fuel line. O lots of things.

 

If it cuts out sharply and dies it is usually electrical.

 

You say the generator needs to be rebuilt? Low voltage can cause ignition problems but usually if the battery has enough oomph to start the car it will run ok for a little while.

Edited September 21, 2015 by Rusty_OToole (see edit history)

[Guest johnjackson]

The only thing that throws me off with fuel supply is that if I have the choke closed it idles up just fine no hesitation

[Guest johnjackson]

Well I switched to an alternator really fast to see if that made a difference and it didn't. I'm going to readjust the floats and see what I come up with because I'm getting consistent fuel pressure. I will let you know what I find. I appreciate the pointers.

[Guest johnjackson]

Alright, well I took the car out and the floats were just a little of so I got those squared away and double checked everything else and it's good. Alternator is charging as should. It has improved a little but still acts like its starving. Did these cars have vented or non vented gas caps? Could that be the issue?

[Guest johnjackson]

Top hat on fuel pump was leaking on back side where I could not see. Looks like a rebuild for the generator and fuel pump will be done.

[vermontboy]

They had a vented gas cap but it usually takes a few miles  for that to stop the car. t

[JACK M]

You have answered your own question.

If it runs better choked then it is starving for fuel. When you pull the choke you are enriching the mixture.

That is an old trouble shooting technique.

 

I mentioned before, check filters and fuel lines. A leaking fuel line may not show fuel spilling but may allow air in when the pump is trying to pull.

Is there a small filter right at the entrance to the carburetor. Often overlooked.

Edited September 22, 2015 by JACK M (see edit history)

[Guest johnjackson]

I replaced the pre filter when I rebuilt the carb. I just ordered a nos fuel pump rebuild kit since that's leaking around the top hat. I'm pulling the electric pusher off. Trying to keep it original as possible. I'll just ensure the fuel system is 100% new lines and pressure check the tank. Cross my t's and dot my I's. Slow but sure for sure to do it right. I really am appreciative of the help on here. Most of the time I usually get pushed away since I'm 28, everyone thinks I'm just going to turn it into a rat rod which is not even close. I love classics for what they truly are and the craftsmanship and art that was created. So thank you for the knowledge.

[carbking]

When you rebuilt the carburetor, did you adjust the metering rods?

 

Easy to do, but MUST be done.

 

Jon.

[Guest johnjackson]

Yes I did, I went threw it twice just to make sure.

[Digger914]

I've never been a big fan of the Carter Carb, when they work, they work great, but rebuilding them can be a real "B" The last carb I rebuilt with a kit, I ended up on the side of the road reinstalling the old metering valve because the new one didn't work for beans. You might want to give this a try.

I see you're in Moundsview, I'm in New Hope and if you're still having trouble with this next week send me a private message, some things are quicker to do than they are to write about and talking is always faster than writing.

[carbking]

The Carter WCFB is one of the easier 4-barrel carbs to work on, and virtually bullet-proof when redone. However, there are a few "gotchas" to be aware of:

 

(1) the afore-mentioned metering rod adjustment

(2) replace the vacuum piston spring (the spring comes in the better repair kits)

(3) often the floats are DIFFERENT, and may be physically interchanged, but not work correctly - http://www.thecarburetorshop.com/CarterFourBarrelCarburetors.htm

(4) as Carter used metering rod technology, the primary jets are larger than the secondary jets

(5) the carbs with the chokes in the airhorn require a one-time modification (as do Rochester 4-Jets) to eliminate a stall on hard turns)

(6) some of the secondary throttle linkage on the early models can be a pain, and should be photographed prior to disassembly of the unit.

 

The only really "bug" in the carb is the fatigue over time of the vacuum piston spring (and they generally are good for a couple of hundred thousand miles). However, even a low mileage carb that is 50 years old may have a bad spring (like coffee and humans, the springs get weaker with age ).

 

Jon.

[Guest johnjackson]

Hey guys thanks for the added advice. Once I get the fuel pump rebuilt I will see how it runs and drives and go from there. I truly hope the new kit solves my problem of gas starvation. I will post tomorrow after I get it rebuilt and will keep you guys updated. I greatly appreciate the help.

I've never been a big fan of the Carter Carb, when they work, they work great, but rebuilding them can be a real "B" The last carb I rebuilt with a kit, I ended up on the side of the road reinstalling the old metering valve because the new one didn't work for beans. You might want to give this a try.

I see you're in Moundsview, I'm in New Hope and if you're still having trouble with this next week send me a private message, some things are quicker to do than they are to write about and talking is always faster than writing.

  

The Carter WCFB is one of the easier 4-barrel carbs to work on, and virtually bullet-proof when redone. However, there are a few "gotchas" to be aware of:

 

(1) the afore-mentioned metering rod adjustment

(2) replace the vacuum piston spring (the spring comes in the better repair kits)

(3) often the floats are DIFFERENT, and may be physically interchanged, but not work correctly - http://www.thecarburetorshop.com/CarterFourBarrelCarburetors.htm

(4) as Carter used metering rod technology, the primary jets are larger than the secondary jets

(5) the carbs with the chokes in the airhorn require a one-time modification (as do Rochester 4-Jets) to eliminate a stall on hard turns)

(6) some of the secondary throttle linkage on the early models can be a pain, and should be photographed prior to disassembly of the unit.

 

The only really "bug" in the carb is the fatigue over time of the vacuum piston spring (and they generally are good for a couple of hundred thousand miles). However, even a low mileage carb that is 50 years old may have a bad spring (like coffee and humans, the springs get weaker with age ).

 

Jon.

[Guest johnjackson]

Got the fuel pump rebuilt

[Guest johnjackson]

Well it's still surging. At a loss at this point and not going to lie my patience has definitely been tested. Not quite sure how many times I can triple check something. The carb is set to spec per manual and adjusted accordingly. Fuel pump rebuilt to spec. Distributor rebuilt. The only thing I noticed was the carb to intake gasket was saturated, any ideas?

[robert b]

john jackson I  would check for vaccum leaks on your in take manifold gasket , or other connections that may be on the manifold , these leaks lean your fuel mixture and can give results like you have stated . Just spray wd 40 or some thing similar on the area where the intake to block gasket is ,if the engine changes speed you have a leak . This is a very common thing as in the last 2 month I had 3 cars with this fault. Bob

Edited September 24, 2015 by robert b (see edit history)

[Guest johnjackson]

I will most definitely try that. Thank you

[vermontboy]

Your saturated gasket might be indicative of a problem with float level or sticking needle valve. Have you tried tapping the carburetor with a good sized screwdriver handle while running ?

 

Did you thoroughly scrape both the carburetor and  manifold mating surfaces ?

Edited September 24, 2015 by vermontboy (see edit history)

[JACK M]

Maybe try an alternative fuel supply, like a boat tank before the fuel pump. That will eliminate everything from the pump back.

I have hooked up a boat tank directly to the carburetor and has a passenger keep pumping the bulb to insure pressure.

Its all trouble shooting.

[Guest johnjackson]

Well here is an update. I found the intake manifold leak so replaced the gaskets and a couple worn out vacuum lines and it has made a huge difference with the overall running and performance of the vehicle. I still have a sputter around 30 mph. Could possible fuel type also be a factor? Should I run mid grade or premium to see if that helps? Yes Vermont boy I did scrape and have made sure my floats and needles are working properly as I thought I might have overlooked something. The carter I'm running has the gasket that has the u shaped opening towards the rear. Can I just itstall the solid style. Honestly I don't think it's seating properly.

[Guest johnjackson]

I would like to say thank you to Digger914 for stopping by yesterday and helping me trouble should and guiding me through a few things I over looked or thought was correct. He really knocked it out of the park. Car runs a whole lot better and have narrowed it down to sloppy carb linkages and or needle valve. So I will try and fix those issues. If no conclusion can be made, well it will get an Edlebrock and an adapter plate. Not the route I want to go but it's worn out and tired and the side of the road is not my idea of a cruise in destination while I wait for a tow truck.

[carbking]

"Car runs a whole lot better and have narrowed it down to sloppy carb linkages and or needle valve."

 

What sloppy carb linkages?

 

Jon.

[Larry Schramm]

If the engine ran fine on the original set up, then there is something missing.

 

I have been there done that and it is usually staring you in the face as being that simple.

[Digger914]

"Car runs a whole lot better and have narrowed it down to sloppy carb linkages and or needle valve."

 

What sloppy carb linkages?

 

Jon.

CarbKing, I bow to your expertise as it's been 15 some years since the last time I chased a bucking carb and back then gas was refined with a different blend.

 

By the time I got to this on Sunday John had already found and replaced the bad intake gaskets and vacuum lines, I meter tested his engine vacuum, reset his timing and we pulled his air cleaner as it was choking the carb. I know these things can be cleaned, but I'm not tooled up for that kind of work.

 

With that done we still had a subtle surge at 30 and John had to tickle the gas peddle to maintain a constant speed. We didn't try it on the highway.

 

The sloppy linkage is front to back, up to down, in and out front shaft play through the carb that allows things to get a little cockeyed and stick requiring a tap on the peddle to drop the feed to idle. I suggested testing with a couple of springs to hold the shaft tight before tearing the carb down and swapping in some old parts as my experience with this type of surging after a rebuild has been fuel metering and I have found that sometimes new parts don't work as well as the parts they replaced, but there was to much play in the shaft to ignore this as a possible cause.

 

Added to this equation since the last time I did one of these is in Minnesota we now have an ethanol blend fuel mandate and finding alcohol free gas isn't as easy as it used to be. I know this can make a difference in jet size, don't know how much.

[carbking]

Digger - the Carter design clearance on throttle shaft to throttle body was 0.004~0.006 inch. The shaft could wear an additional 0.003 without issues. Measure the clearance with a dial indicator. If it exceeds 0.009, then bushings or throttle shaft can correct the issue.

 

The throttle clearance can certainly make a difference at idle, but at 30 MPH the throttle clearance should have no effect. We have had tractor carbs come in with HALF of the throttle shaft gone! The governor would move the shaft back and forth wearing the shaft. Engine would not idle at all, but would run PTO speed with no issues.

 

With no offense meant to the rebuilder, the four most common causes of a surge such as you describe are (1) interchanging the primary/secondary jets (the large ones are the primary), (2) interchanging the primary and secondary floats (see the link in my previous post), (3) the metering rod/vacuum spring setting, and (4) lately, ethanol in the fuel has less energy, thereby requiring somewhat additional fuel.

 

Check (1), (2), and (3) FIRST before attempting to compensate for the ethanol. A simple test to determine what effect a richer jet would have is to add 1/32 inch to the primary fuel level in the bowl and see what happens. Carbs are quite sensitive to float setting. If the surging disappears, then one size richer (+ 0.002) primary jet is in order. The higher bowl level is a test, not a fix. Permanently leaving the fuel level too high could cause fuel bleed-over when parked on an incline.

 

Yes, trying to troubleshoot a 60 year-old carb can be frustrating; but these things are virtually bullet-proof once dialed-in. While technologically dated, they are much more reliable than any carb made in the last 20 years. And the technology isn't bad.

 

Jon.

Edited September 29, 2015 by carbking (see edit history)

[Digger914]

CarbKing, Thanks for the reply.

 

Didn't know these bushings were still available. Did bring a Dial Vernier with when I went to look at the carb, didn't need to use it as the play was that obvious.

 

Do you have a source for bushings and shaft if necessary?, vac spring too, just in case, don't know if Johns rebuild kit came with one and didn't think to ask.

[carbking]

Digger - will need positive identification (tag number) of the carb, but yes, our kit DOES contain the spring, and we have aftermarket bushings. Throttle shaft availability depends on the carb number, don't know until I know the number. Again, the throttle shaft play, while definately effecting idle quality, should not effect a surge at 30 MPH. But the vacuum spring and ethanol fuel certainly can.

 

Oh, and if the tag is missing, get the number from the metering rods, and the airhorn; we should be able to figure it out.

 

Jon.

[Guest johnjackson]

Hey carbking, I can definitely get you the info, I'd tag is still intact. I will get on that as soon as possible as well as measuring play in the primary.

John

[Guest johnjackson]

Alright, well here's an update. I bought an Edlebrock 1406 600 cubic feet per minute carb and adapter that I will put on momentarily for the rest of the driving season since I'll have all winter to really dig into the carb. Once the carter is good and ready it's going back on and the Edlebrock will be my back up. I'll get that info to you carbking about the numbers and discipline in the linkages.