VERY hard to start after the car sits for a day or more.

[timk225]

My 1973 Duster, 225 1 bbl 1920 Holley, 904, had been running pretty well, or as well as you can expect out of a stock 1 bbl Slant 6. But lately it has developed a new trick. It does not like to cold start after it sits for a day to a week.

It takes a hell of a lot of cranking, interspersed with a hell of a lot of pumping the gas to get it going. I'm talking 30 or more pump shots of fuel, maybe 50!

Once it fires though, it starts right up and idles nicely like nothing is wrong. Very strange. And if I drive it here and there, it doesn't take more than one or 2 gas pedal pumps, sometimes none, to restart it.

I'm wondering what's wrong here. Imagine it. Just pump pump pump, crank crank, pump pump pump crank crank, pump pump pump, crank crank, pump pump pump crank crank, pump pump pump, crank crank, pump pump pump crank crank, pump pump pump, crank crank, pump pump pump crank crank, pump pump pump, crank crank, pump pump pump crank crank, for no clear reason I can see.

One person offered the idea that the fuel was getting evaporated out of the intake manifold while it sat. It is running 90 octane ethanol free gas from Sheetz. Maybe but this was never a problem over the last few months.

Today I was doing the pump pump pump thing, and thought the pump shots were looking pretty weak, so I tapped the 1920 fuel bowl area with a big wrench about 20 times, then cranked it to fill the bowl, then the pump shots looked a lot stronger. But it still took a good 15-20 pumps to get the engine going.

I don't think it is a vacuum leak.

Any ideas?

 

[slantsixdan]

Once it fires though, it starts right up and idles nicely like nothing is wrong.

Idles nicely at what speed? Fast (1,200 to 1,500 RPM)? Or the same slow (750-ish RPM) speed as it idles after you've been driving it awhile? Because one easy possible cause here is a faulty choke that's not closing. Have you checked? Next time the engine is cold, remove the air cleaner lid. Use one hand to hold the air cleaner housing down firmly on the carburetor as though the lid were holding it down (don't skip this) and your other hand to pull the throttle cable as though someone in the car had pushed the accelerator to the floor and then released it. If the choke plate does not snap all the way closed as the accelerator cable is pulled, the choke is faulty.

The reason for holding the air cleaner body firmly down is that one cause for the choke not closing is that the air-cleaner-to-carburetor gasket fails, and the air cleaner body is now slightly lower…sometimes just enough lower that part of it interferes with the choke lever, which can no longer close. So test two, if the choke plate didn't close, is to lift up the air cleaner housing and pull the throttle cable again. Does the choke close now? Replace that gasket.

The 1973 choke thermostat is a 1-year-only item, and it was never a particularly well-behaved setup. Also, it is not adjustable. Even if it's no more faulty than when it left the factory, you'll have much better cold-start/cold-running behaviour with the № 1231 electric choke kit, which is easy to install in place of the factory parts and is fully adjustable.

Now, it's also possible the choke closed but your fast-idle cam didn't swing into position (link fell out or broke, fast-idle cam screw backed out, link and screw in place but fast-idle speed screw backed out). If so, fix those issues.

If your choke and fast-idle setup are working perfectly and the car still does this, your carb is emptying out overnight. Leaky inlet needle and seat, leaky bowl-to-body gasket, leaky main-well-to-body gasket, combined with a less-than-fully-happy fuel pump.

Carburetor operation and repair manuals and links to training movies and carb repair/modification threads are posted here for free download; additional tune-up parts and technique suggestions in this post.

 

[toolmanmike]

Fuel evaporation would be my guess. You really don't need to pump the pedal off it's hinges. A couple pumps will give it enough fuel to start (If there is any in the carb bowl) Before you start it, take the air cleaner off and open the throttle as you look down the carb for fuel squirting from the accelerator pump nozzles. No fuel, no start. You may have a break or crack in a line or hose or even sone different gas that you ran last tank full. Many here have experienced the same issue and if all looks good, they installed a electric charge pump near the tank to "prime" the system. Here's a link. Electric primer pump for fuel

 

[trapster]

Fuel evaporation would be my guess. You really don't need to pump the pedal off it's hinges. A couple pumps will give it enough fuel to start (If there is any in the carb bowl) Before you start it, take the air cleaner off and open the throttle as you look down the carb for fuel squirting from the accelerator pump nozzles. No fuel, no start. You may have a break or crack in a line or hose or even sone different gas that you ran last tank full. Many here have experienced the same issue and if all looks good, they installed a electric charge pump near the tank to "prime" the system. Here's a link. Electric primer pump for fuel

What He said.

 

[Dana67Dart]

IMHO you are flooding the engine.


first before you cold start pulling off the air cleaner and with a flash light look down the carb and pump the linkage 1 time, if you don't see the accelerator pump squirt file into the carb down the following

Do not pump the gas just crank the engine for about 10 seconds then repeated the above.

If it squirts now you have fuel EVAP.

If you got squirts the first time than there is no fuel EVAP

If you drive it 1 day ago the 2 pumps and about 3-5 seconds of cranking , might need to repete.

If it's been a week, 2 pumps hold the throttle 1/2 open and crank 3-5 seconds, then 2 more pumps and 3-5 seconds of cranking.

This has worked on my 67 273 2 bbl and my sisters 65 mustang 200 in 6 with a 1 bbl carb.

 

[slantsixdan]

Folks…

Those would be good answers you're giving him if he'd just bought this as his first-ever carbureted car and didn't know correct starting procedures.

The way I read his post, that's not the case. It reads to me like it was starting easily from cold, and now suddenly it's not. Which means it's a lot more likely that something broke or failed, and a lot less likely that he suddenly forgot how to start his car.

 

[timk225]

During the last year while I've been getting the car back on the road, the entire fuel system has been replaced. Lines, tank, pump, etc. And even with good pump shots coming out of the carburetor, it still takes many pump shots to get it running if it has been sitting for days.

As a test, last night when I got home, I came out to the car just before going to bed, so the car had about 3 hours to sit. One pump and it started right up. Then this morning, after 6 hours of sitting, 3 pumps and it was running.

It is possible I got some bad fuel, as the problem has only ever happened in this particular tank of gas. Last time I filled it was 3-4 weeks ago. With no working A/C in the car, it has been way too hot to drive it lately, so I stayed in my Tesla Model 3.

We finally have a couple cooler days today and tomorrow, and the "head paycheck writer" at work is supposed to be visiting my place today, so I wanted to have this car at work, I think he'd appreciate it. The last two times he came up, either I was doing work on the car or it was too hot then also to drive it.

 

[Icetech]

Easy test for the evap theory (which i don't buy.. mine sits for weeks and fires right up) Let it sit for a day or 2 and take off the air cleaner and pump the carb.. see gas squirt? then it's not evaporating..

When cold is your choke closing all the way? With my car it's 1 pump and it fires almost instantly (newer carb with electric choke), Even my big block cars without a choke were 2 pumps then crank.

Also, are you sure your accellerator pump is working ok? plenty of squirt when you test it? That would cause your issue...

Hard starts are a pet peeve of mine.. can't deal with it

 

[toolmanmike]

Easy test for the evap theory (which i don't buy.. mine sits for weeks and fires right up) Let it sit for a day or 2 and take off the air cleaner and pump the carb.. see gas squirt? then it's not evaporating..

When cold is your choke closing all the way? With my car it's 1 pump and it fires almost instantly (newer carb with electric choke), Even my big block cars without a choke were 2 pumps then crank.

Also, are you sure your accellerator pump is working ok? plenty of squirt when you test it? That would cause your issue...

Hard starts are a pet peeve of mine.. can't deal with it

Evaporation has a lot to do with the fuel quality. I buy the non ethanol premium at the same place for my old cars. I filled up before heading to MITP and turned around after I developed a bad surge. No issues until I filled up. Talked to a friend that buys his gas at the same place and he and half a dozen friends had experienced fuel issues the same time as I did. Sometimes mine will start up easily after setting and other times I have to crank on it a while. The only thing that changes is the fuel in the tank. We can't diagnose the OP's issue over the internet. We can only speculate what it may be from what we have experienced with our own cars. Kwik Star used to have 93 non ethanol. Now their 91 is crap. There is a privately owned Phillips 66 station nearby that has premium. I need to try theirs.

 

[Icetech]

Evaporation has a lot to do with the fuel quality. I buy the non ethanol premium at the same place for my old cars. I filled up before heading to MITP and turned around after I developed a bad surge. No issues until I filled up. Talked to a friend that buys his gas at the same place and he and half a dozen friends had experienced fuel issues the same time as I did. Sometimes mine will start up easily after setting and other times I have to crank on it a while. The only thing that changes is the fuel in the tank. We can't diagnose the OP's issue over the internet. We can only speculate what it may be from what we have experienced with our own cars. Kwik Star used to have 93 non ethanol. Now their 91 is crap. There is a privately owned Phillips 66 station nearby that has premium. I need to try theirs.

True but seeing if it pumps fuel before starting it would help diagnose if the carb is losing it's fuel overnight or in a few days

 

[toolmanmike]

Fuel evaporation would be my guess. You really don't need to pump the pedal off it's hinges. A couple pumps will give it enough fuel to start (If there is any in the carb bowl) Before you start it, take the air cleaner off and open the throttle as you look down the carb for fuel squirting from the accelerator pump nozzles. No fuel, no start. You may have a break or crack in a line or hose or even sone different gas that you ran last tank full. Many here have experienced the same issue and if all looks good, they installed a electric charge pump near the tank to "prime" the system. Here's a link. Electric primer pump for fuel

You have to start diagnosing somewhere and the OP thinks that pumping the carb 50 times makes it start. After cranking for a couple min. he said all of a sudden it starts and runs pretty good. Does it have fuel to start? Does the choke work? If there's no fuel in the carb, where did it go? Leak, drainback, or evaporation.

 

[toolmanmike]

True but seeing if it pumps fuel before starting it would help diagnose if the carb is losing it's fuel overnight or in a few days

Exactly. See my post #3. Take off the air cleaner and have a look.

 

[Icetech]

Exactly. See my post #3. Take off the air cleaner and have a look.

wait.. there was stuff to read? damnit.... missed it

 

[TF360]

Check all your new fuel line connections for any leaks or kinks. Maybe the new fuel pump is no good.

 

[timk225]

I do take the air cleaner cover off to watch the accelerator pump while I work the throttle by hand. It is pumping a lot of fuel into the intake, but even so, it takes a lot of fuel to start up. Once it is running it acts normally, it is just that first start after sitting a day or more that is a weird problem.

Last night, the car was down to around 4 - 5 gallons of gas remaining in its tank, and I added 7 gallons from gas cans I had sitting for about a month and a half. Didn't want to let it sit around for too long. I'll watch and see how it starts the next few days or week, and see if anything changes.

I don't think it is a vacuum leak, I changed some vacuum lines recently and checked with a gauge, it seems to be good. Around 18-20 inches when revved lightly, about 16 at slow idle.

With the engine cold, the choke is about 1/4" from fully closed. It is the stock exhaust manifold heat riser choke rod mechanism for the Holley 1920. The electric wire is broken off / gone.

 

[TF360]

Do you think you are Flooding it? On my Slant, I push the pedal down about half way (only once) turn the key and she cranks right up after a day or two

 

[toolmanmike]

Do you think you are Flooding it? On my Slant, I push the pedal down about half way (only once) turn the key and she cranks right up after a day or two

Exactly how it should work.

I do take the air cleaner cover off to watch the accelerator pump while I work the throttle by hand. It is pumping a lot of fuel into the intake, but even so, it takes a lot of fuel to start up. Once it is running it acts normally, it is just that first start after sitting a day or more that is a weird problem.

Last night, the car was down to around 4 - 5 gallons of gas remaining in its tank, and I added 7 gallons from gas cans I had sitting for about a month and a half. Didn't want to let it sit around for too long. I'll watch and see how it starts the next few days or week, and see if anything changes.

I don't think it is a vacuum leak, I changed some vacuum lines recently and checked with a gauge, it seems to be good. Around 18-20 inches when revved lightly, about 16 at slow idle.

With the engine cold, the choke is about 1/4" from fully closed. It is the stock exhaust manifold heat riser choke rod mechanism for the Holley 1920. The electric wire is broken off / gone.

Does the choke butterfly close after the first pump of the gas? It should. If you have a working choke and a squirt of gas there is no reason it won't start cold. It should work like TF360 just mentioned.

 

[TF360]

Do a Tuneup on it. Plugs, Cap, Rotor etc.

 

[slantsixdan]

I do take the air cleaner cover off to watch the accelerator pump while I work the throttle by hand. It is pumping a lot of fuel into the intake,

If you can see that happening, it means the choke plate isn't closed.

With the engine cold, the choke is about 1/4" from fully closed. It is the stock exhaust manifold heat riser choke rod mechanism for the Holley 1920. The electric wire is broken off / gone.

There y'go, thought so. The choke needs to close. And that broken-off wire means even if your existing choke were working correctly, it would be slow to open and you'd waste a lot of gas. Do as I described in post #2 of this thread; get the № 1231 electric choke kit, install per included instrux, adjust with intel from the factory service manual + the carb info I linked you to + this article, and you're all set to go.

 

[Swinger 340]

Evaporation has a lot to do with the fuel quality. I buy the non ethanol premium at the same place for my old cars. I filled up before heading to MITP and turned around after I developed a bad surge. No issues until I filled up. Talked to a friend that buys his gas at the same place and he and half a dozen friends had experienced fuel issues the same time as I did. Sometimes mine will start up easily after setting and other times I have to crank on it a while. The only thing that changes is the fuel in the tank. We can't diagnose the OP's issue over the internet. We can only speculate what it may be from what we have experienced with our own cars. Kwik Star used to have 93 non ethanol. Now their 91 is crap. There is a privately owned Phillips 66 station nearby that has premium. I need to try theirs.

I had the same problem with "Winter gas", a vapor lock. Once the motor cools, it will start. As for other starting issues here is often the accelerator pump diagram will fail. If you use only ethanol in a carb, it will fail as other rubbers in the carb. Try to find a leather pump plunger, if you can.