ClassicCar

hdsn49

Two years ago I had my carburetor professionally rebuilt for my 1949 Super Six Brougham. My son and I installed the carburetor and adjusted everything to specs we were given. The car starts and runs fine until you try to drive it. It keeps stalling as you come to a stop. The engine will fire right up and then will stall again once you let off on the gas as your coming to a stop. I have avoided driving the car for two summers now. I only drive it around the block.

We have checked the timing, the points, the spark plug gap etc. everything is fine. My son Matt wanted to take the car today for the filming of "Chasing Classic Cars" with Wayne Carini. Wayne called Matt because he bought another Hudson for his personal collection. He wanted Matt to be part of the filming because he knows that Matt comes from a Hudson family and has known the owner of the Hudson his whole life. Unfortunately I wouldn't let him take the car.

rambos_ride

hmm..sounds to me like the float level might be off and closing the needle seat - is it only stalling during slowdown/braking..or does it also happen on hard cornering too?

Jon B

It wouldn't be the needle valve itself, would it? A bit of dirt in the line? A quick, deft tap with a hammer could fix that very quickly.

hdsn49

Only happens during slowdown/braking.

walts garage-53 · walts garage-53 December 2012 Posts: 1,470Platinum Member

Walt here; your idle jets are blocked with varnish and the 2 anti percolator valves are staying closed. Has to be set with the correct tools. Your carb must be WDO #647s 2 barrel. Should have the std metering rod #75-686.

J Spencer

Have you checked it thoroughly for a vacuum leak around the base of the carb or a cracked intake manifold???

RonS

I tend to agree with Walt. Sometimes you can get lucky by reving the engine and using your palm to choke off the air for a split second & before it stalls release your hand. But in all fairness, modern gas evaporates in a couple of months leaving creme' brulee in the float chamber and ports, and most vulnerable is the idle circuit.These old vented fuel systems require start up and running at least once a month. My friend had the same issue with his 50 Dodge. Idle port was crystalized. Maybe by removing the idle adjustment screws and blasting Gumout in the holes, then replacing the screws, you might avoid a dissassembly.

JasonNC

My Hudson did something very similar yesterday. It ran well on the open road until I sat in line at Wendy's and then again when I let it idle at my mother's house before I got back on the highway. Both times it acted as if it wanted to stall out for a few seconds when I first took off and then smoothed out and ran well again. I chalked it up to vapor lock since the temps were in the 70's.

Clutch guy

sounds like the valves are to tight

Geoff C., N.Z.

My advice would be to check for too high a float level, and not enough lift of the anti-percolator valve.

Uncle Josh

My Commadore did the same thing. I did what Geoff suggested and lowered the float about 3/32. End of problem. The gas level was too high and slopped over into the intake when braking. As Geoff points out in another place, the Alcoholgas is not dense enough to raise the float far enough with the float at the old spec level.

Same thing happened on an old Pontiac with a plastic foam float that gas-logged. In that case a new float fixed it.

If the anti-perk valves aren't adjusted correctly, it will let pressure build from heat after you shut the engine off, and force gas into the intake, causing hard starting.

If the float adjustment doesn't fix it, then you probably have the condition Walt suggested and may want to have him fix them.

Park_W

Can you narrow the possibilities with a little more info on the history? Since the carb was installed, has the car sat for some time without being driven? Did this problem arise suddenly, or over some period of time?

hdsn49

Park, My son and I installed the carb last summer 2011. My son drove the car to a show and had problems all the way there and back. We double checked everything. The fall came and we put it away for the winter. This spring we tried again to drive the car. We encountered the same problem. We double checked the timing, dwell and checked for vacuum leaks. One time this summer we were able to drive the car around the block for about 20 minutes without a problem. When I tried driving it on Monday it kept stalling again.

I can start the car and let it run for 10 to 20 minutes in the driveway without problem. I can rev up the engine and it won't stall. We take it out on the road and it stalls when you come to a stop sign or light.

Jon B

'49, did you not have similar problems before installing the new carb? (Maybe you had problems, for example, but they were different from the ones you're having now?)

Have you contacted the carb rebuilder and explained the problem? Even though you're surely past the warranty period, they may agree to take a look at it if you'll return it to them.

I had a carb rebuilt by Daytona Auto Parts several years ago. I bolted it on my and immediately had problems. I assumed they were anywhere BUT the carb, since it had been rebuilt. After an afternoon of checking timing, wiring, everything, an onlooker suggested we pull a spark plug and we found no gas in the cylinders! Through some miracle, the fellow at whose house I was doing this, had an old rebuilt 1937 carb in the box, amongst the stuff in his basement, and when we installed that, the car ran perfectly!

I sent the rebuilt carb back to Daytona and when they sent it back, the think worked perfectly. Which it has done ever since.

Don't assume that since the carburetor was rebuilt, that it's NOT the source of your problems!

RonS

I'm getting some more info here. As you say it will run for 20 min, in neutral & reving, then releasing in neutral won't shudder or stall it? Can you start up cold and drive off with out stalling ? I mean does the condition only appear when the engine is fully warm and the choke valve is open. I still like idle jet( dirt?), but, I had a Met with a bad intake gasket. In order to keep her running, I needed to keep the choke out all the time. Push it in & too much air... starvation and off. But a vacuum gauge showed evidence of a leak. Curious, what is your curb idle RPM at fully warmed/ choke open? If you bump up the idle speed 50 to 100 rpm does the stalling stay? What about opening ( CC) the idle jets 1 turn ea ? Do one at a time. Get back to us.

onerare39

I had the exact same experience in 2009-2010, it was vapor lock. I added an electric fuel pump and a return line, it solved the problem.

RL Chilton

I had the exact same experience in 2009-2010, it was vapor lock. I added an electric fuel pump and a return line, it solved the problem.

John-

Same with me and the '52 Sedan. Solved it exactly as you did. I could drive a couple hundred miles, but when we went in to make a stop, it would quit. I wasted no time in installing the elec. pump and return line in the convertible, as well.

RonS

I believe that the car will not start right up if vapor lock is present. You must wait until the engine cools, or at least the fuel pump. However a weak fuel pump could be a factor. I also agree to install an electric pump for a variety of reasons. Does the car do the same thing this time of year when the temps are cool( or cold). Many folks have V- lock when the air temps reach 90+ and air flow drops, such as waiting at a long traffic light, then accelerating in traffic. Fuel starvation, or flat out stalling, will occur. All the years I had those issues. The car ran great until summer temps arrived. 6 mos of the year in Arizona. Then I sent out my AC fuel pump to Then & Now. Added 1 extra gasket, that pushed the PSI to 5 ( with Craig valves) and voilà ,2 years no grief.
Russ, I sent you a PM ??

RL Chilton

Ron-

Didn't get it. Send me an e-mail to: HETrlchilton52@gmail.com (drop the HET).

RonS

OK. I wonder why it didn't send. It says I sent it on my end.

RL Chilton

Maybe it's operator error on this end. Replied to your e-mail.

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