[fyrffytr1]

I have a 1939 Pontiac Series 28 sedan that I recently started playing with and was able to get the motor running after sitting for 50 years. I was even able to drive it around in my back yard as the clutch worked. But, I found out too late that I didn't have brakes! The parking brake froze up when I pulled the lever and the car barely slowed down. I was only in first gear so I shut the motor off and hoped it would come to a stop, and it almost did, before I hit a cedar stump. Since I had taken the whole front end off to work on the motor the radiator was what hit the stump and it got pushed back into the fan just enough to bust a hole in it. Luckily it was not the original radiator but a spare I had laying around.
Anyway,to make a long story even longer I got the parking brake freed up but ran into a problem with the carb. I am feeding it from a 6 volt inline fuel pump and a 5 gallon gas can. The carb is rebuilt but every time I try to start the car I have to squirt gas down into the carb. The motor starts right up then but no matter how long I let the thing run, if I shut it off I have to prime the carb manually before it will fire again. I was told it is the accelerator pump but if that was the case wouldn't the motor stumble when I rev it up? Once running it responds smoothly without any hesitation.
So if anyone has stayed here long enough to read this what should I look for?

[77 TRASHCAN]

Calling Jon Hardgrove!!!

[Greg Reid]

I don't know diddley but does the bowl have any gas in it after it sits for a while? If you pump it first thing, do you get a squirt?

["QUICK-SILVER"]

First I'd try richening up the idle mix a hair.

And might need to hand choke it to make it light off.

Them old straight engines can be tempermental when cranking if spark ain't strong and if the starter spins it over slow. Choke helps a bunch with slow spinning.

Treat it like you would an old farm tractor when cranking.
Clay

[fyrffytr1]

Originally Posted by Greg Reid

I don't know diddley but does the bowl have any gas in it after it sits for a while? If you pump it first thing, do you get a squirt?

Greg,
I can shut the car off and immediately try to re-start it but without a shot of gas into the carb it won't start. Once I give it a shot it starts immediately.

[fyrffytr1]

Originally Posted by "QUICK-SILVER"

First I'd try richening up the idle mix a hair.

And might need to hand choke it to make it light off.

Them old straight engines can be tempermental when cranking if spark ain't strong and if the starter spins it over slow. Choke helps a bunch with slow spinning.

Treat it like you would an old farm tractor when cranking.
Clay

It's got an automatic choke that works. Cold or hot, once I give it a shot of gas it starts right up.

[carbking]

EDIT: after posting, had an afterthought, do a compression test. With good compression, that engine should easily start once it has been run WITHOUT the need for a squirt of fuel.

Test the accelerator pump.

(1) put on a pair of goggles
(2) start the engine
(3) stop the engine
(4) remove the air cleaner
(5) open the choke butterfly and hold it open
(6) work the throttle from closed to wide open, watching below the choke butterfly for a squirt of fuel, do it again.

If you do NOT see a squirt of fuel, rebuild the carburetor
If you DO see a squirt of fuel, then I don't know.

Jon.

[hgiv]

Couple thoughts... but i'm no carb guy so your mileage will vary!

First thought is that your probably not getting much gas to that carb. If you were able to really run it on the open road you might find that out. When the car gets running is sort of "pulls" the gas but when not running there isn't enough pressure in the pipes. Try checking that fuel pump. See how well it pumps when disconnected? That being said you should still have fuel in the bowl and enough fire juice to get it to pop off... especially when hot. Someone else asked about the bowl? Is there gas in it? Same issue with the bad accelerator pump. The car will pull enough gas to go even with the bad pump but it won't go well and starting is an issue. Test on it.

I know you said that the carb was rebuilt but honestly if I had a dollar for every guy with a carb problem who started with "it's recently rebuilt..." And even if done right one shot of crappy old or dirty gas can ruin that right quick! A running engine will "run" even with a seriously defective carb. But it won't run well.

[fyrffytr1]

Originally Posted by carbking

EDIT: after posting, had an afterthought, do a compression test. With good compression, that engine should easily start once it has been run WITHOUT the need for a squirt of fuel.

Test the accelerator pump.

(1) put on a pair of goggles
(2) start the engine
(3) stop the engine
(4) remove the air cleaner
(5) open the choke butterfly and hold it open
(6) work the throttle from closed to wide open, watching below the choke butterfly for a squirt of fuel, do it again.

If you do NOT see a squirt of fuel, rebuild the carburetor
If you DO see a squirt of fuel, then I don't know.

Jon.

Thanks, If the carb needs rebuilt do you do it?

[shaker455]

Originally Posted by fyrffytr1

I have a 1939 Pontiac Series 28 sedan that I recently started playing with and was able to get the motor running after sitting for 50 years. I was even able to drive it around in my back yard as the clutch worked. But, I found out too late that I didn't have brakes! The parking brake froze up when I pulled the lever and the car barely slowed down. I was only in first gear so I shut the motor off and hoped it would come to a stop, and it almost did, before I hit a cedar stump. Since I had taken the whole front end off to work on the motor the radiator was what hit the stump and it got pushed back into the fan just enough to bust a hole in it. Luckily it was not the original radiator but a spare I had laying around.
Anyway,to make a long story even longer I got the parking brake freed up but ran into a problem with the carb. I am feeding it from a 6 volt inline fuel pump and a 5 gallon gas can. The carb is rebuilt but every time I try to start the car I have to squirt gas down into the carb. The motor starts right up then but no matter how long I let the thing run, if I shut it off I have to prime the carb manually before it will fire again. I was told it is the accelerator pump but if that was the case wouldn't the motor stumble when I rev it up? Once running it responds smoothly without any hesitation.
So if anyone has stayed here long enough to read this what should I look for?

What carb is it ? post a pic.
I may have an accel pump in stock

[fyrffytr1]

I thought I found my problem. I took the lines off the inlet and outlet of the fuel pump and saw something stuck in the inlet port. It was a wasp! It must have been in the fuel line when I bought it. The line is new and has been sealed since I got it. I put it on the pump as soon as I got home and stuck the other end in the 5 gallon can to try starting the car.
Anyway, that still wasn't my problem. I tried what carbking said and could only see a very light dribble of gas when I hit the accelerator pump. Since I don't know how long ago this carb was rebuilt I am going to have it completely gone through.

[Schurkey]

Is that Hudson's Hornet?

[fyrffytr1]

Maybe I will get the bugs worked out sooner or later!

[formula kid]

If that wasp was in the fuel filter what else is in there? First try a new filter and see if that helps your fuel flow. Then rebuild the carb if it doesn't get better.

[Sirrotica]

One other thing to check is your symptoms are pointing to a lean mixture. Being the car is 70 years old are you sure the manifold gaskets are sound, and the bolts holding the manifold to the engine aren't loose? It sounds to me you could have a major vacuum leak. Just something else to check from the symptoms you're describing.

I'd also take an old spark plug and check to see if you have a hot spark when it won't start. A weak spark may make it harder to start, but it would still run once you got it fired up. The way the engineers wired the ignition system is that when the starter is engaged it sends battery voltage to the points so it has a hotter spark, after releasing the key it goes back to resisted voltage. On a 6 volt system 3 1/2 - 4 volts is the voltage when the starter isn't engaged, 6 volts while the starter is engaged. While cranking it you should have a blue spark with a test plug.

From the few flathead Pontiacs I've work on, many years ago, I know they have low compression, and if the rings are worn badly they have a weak vacuum signal. Any idea of what the compression is? I've seen really bad rings make an engine difficult to start, especially when it's cold.

Maybe you'll find something, or maybe I'm shooting in the dark here. Anyway if I was troubleshooting the problem I'd try those things before trying to get someone to rebuild the carb. Finding a kit may, or may not, be challenging. Checking the things I listed will cost some time, no cash outlay.

[carbking]

"Maybe you'll find something, or maybe I'm shooting in the dark here. Anyway if I was troubleshooting the problem I'd try those things before trying to get someone to rebuild the carb. Finding a kit may, or may not, be challenging."

Finding a rebuilding kit for virtually any USA-produced carburetor up through 1974 is NOT challenging

"Thanks, If the carb needs rebuilt do you do it?"

Not any more, but might have one ready to go, look for the tag number, and give me a call. Should be a Carter type WA-1, with tag number 432S. However, it may have been replaced sometime in the 80 years.

Jon.

[carbking]

Your carburetor should resemble this one, albeit with a bit more grime:



This one is new old stock, with patina.

Jon

[flat-bill]

You do know that this is not a fuel injection car. It is VERY common to have to tap the gas pedal a time or two before spinning the engine over to get it to start. Billk

["QUICK-SILVER"]

Originally Posted by "QUICK-SILVER"

First I'd try richening up the idle mix a hair.

Have you tried opening up (backing out) the idle mixture screw yet?

This flathead isn't like overhead valve engines. Intake tract turns up in the block to get to the combustion chamber. Idle mix adjusted for highest speed and highest vacuum will be too lean for cranking without pumping the gas pedal.

Try backing it out till idle starts to slow down but not to the point of puffing black smoke.

Clay

[fyrffytr1]

Thanks for all the replies and tips. I may have a vacuum leak or 7! I will check everything out and let you know what all I find.