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How should a classic Mustang start?

36K views 51 replies 34 participants last post by  GypsyR  
#1 ·
I had a 65 Mustang with 302 engine (4brl carb and auto choke) and C4 trans.
People around me are convinced that a proper way to start the engine is:

If engine is COLD:
- push accelerator pedal down 3 times (that should pump the gas),
- leave accelerator pedal UP and turn the key and start the engine

If engine is HOT:
- Don't pump the pedal, just push it DOWN and hold,
- turn the key and start the engine then lift the pedal

I'm not sure this is correct or needed?

My biggest problem with that engine was, that when i don't run it for a week, i can't start it. I takes a lot of tries to make it or i feel sorry for starter and just pour little gas in the carburator. That way it starts immediately. If i ran it every day, there was no problem starting it.

Now i'm getting 69 Mustang with 302 engine and MSD ignition so i hope starting would be easier.
 
#2 ·
Possible battery drain..?
When I left my car for over a week or more, it's also tough to start it. I just need to push the accelerator pedal 1-2 more times and go.
Normally, I just need 1 (maybe 2) accelerator pushes to pump gas into carb. Then push it half-way down at the same time you turn on the key.
Many pedal pushes will make a flooded carb and the car will not start or it will take plenty of time until gas evaporates.

Josep
 
#3 ·
They all have their little quirks. Mine was different from yours (hot vs. cold) ideally they all fire up in both conditions except if flooded and then you clear it with the gas pedal. Aside from the long start after sitting... I was getting some drain back and the bowls needed to refill after it sat for a while.
 
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#4 ·
Here's the sunvisor sticker that show how to do it, but Frank is correct, every car has their own quirks.

Josep
 

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#5 ·
My 68 289 was also like that. Leave it sit for more than a week & I would have to crank it on the starter for maybe 15 seconds to suck up fuel from the tank. This didn't bother me 'cause due to the cranking I knew there would be oil everywhere in the engine when it fired up. Now with the 331, PMGR starter & Summit carb, together with a Mallory Unilite ignition ,I just have to wave the ignition key in the general direction of the car & it starts right up. LOL
 
#7 ·
I experience the same issue when my car has been sitting for over a week. I would have to crank it for 10 to 15 seconds before it would fire. I started pumping the gas pedal 5 to 6 times slowly before turning the key and it will fire up right away. If it has only been sitting for a day or two, it has no issues.
 
#8 ·
Starting most of these early carb'd engines, is about the same as you have outlined. The state of tune, heat factors, choke operation, battery condition, will way in at any given time. This goes for that '69, as well.
Your mission, should be to learn how to diagnose each of the systems to determine which is failing to do it's part in cranking, firing, and running. Just the way I see it....
Happy Trails
 
#15 ·
The gas is NOT going to evaporate out of the float bowls "very quickly" as posted (#6) it would do. Heck, it's nots going to evaporate in a month.

If the OP has to our raw gas down the carb throat for easy starting then it's for certain that the accelerator pump (and possibly the choke as well) is not functioning properly.
Z
Exactly as Z spoke. The gas don't go away that fast. One day, one week, one month and mine starts pretty much exactly the same.

1. Pump the pedal once (twice if I left it outside like this morning and it was 37F)

2. Bump the starter. Seldom does it not fire on a one second bump of the starter.

3. When it's cold like this morning I had to catch it once with a small blip of the pedal so she would not die.

Warm starts after driving.

I may or may not press the pedal down a little while cranking. It starts the same either way. Takes 2-3 seconds of cranking and then fires up every time.
 
#10 ·
The gas may not be evaporating but it sure as heck goes somewhere after 7-10 days. I have a clear filter and can see when it is empty. It is at a slight angle so not all of the fuel could drain back if it wanted to. Where that bit of fuel rests in a crook of the filter it will disappear and leave a reddish spot of what i'll call varnish in the filter. It makes me cringe thinking what that is doing inside the carb.
Save you starter and dont spin it for 30 secs at a time or even 15 as far as i'm concerned. It takes 4-5 seconds to see fuel fill my filter, pause, another 4-5 secs and i'm sure there is adequate fuel in my yuge road bowls, pause, then it usually fires after 3-4 more secs of cranking. That's after a long sit. My bowls hold prol 5 or more ounces each, where did that gas go within two weeks?
I've never agreed with pumping the throttle to prime it unless the engine is turning. It just has to be more efficient to spray the fuel as it sucks it in or it's pooling inside the intake.
If its a restart within an hour of so it should fire immediately, if it doesn't within 2 secs gently get on the throttle and begin to depress more and more till it fires, the first bit of throttle will work the acc pump, keep opening and cranking even if you foot gets to the floor because by then its prol flooded and need all the air it can get. Your friends saying to floor it is not completely wrong, I just don't want it to rev and roar so much at start.(squeals my belts)remember if you release and get back on the throttle you are working the acc pump again possibly making things worse.
You have to be your own computer when starting an older car like this. Calculate engine temp, air temp and try to deliver just enough fuel and air. I use a manual choke to remove one of the problem variables.

I've been meaning to get one of these bottles, you can fill your carb bowls through the vent tubes
I snicker when people say they want to get a classic car because they are simple :)
TMI?:nerd:
 

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#13 ·
That's one thing I love about my car, I've done work to it where it's sat 2-3 months at a time and will fire right up even if I left the battery connected. My C10... eh... it's got some electrical gremlins... if I don't drive it at least once a week it will kill the battery.

As far as starting... my car typically sits 3-5 days during the week before it's run again. I usually let it turn over for 5-10 seconds to get the oil and fuel moving. THEN, I'll give it one shot on the pedal and it fires right up. When hot, I have to do what that visor cardboard thing says, I have to push pedal about halfway down and hold, otherwise it will take forever to start. It's great that I have a working ebrake again, makes this much easier.
 
#12 ·
I think the original owners manual has a different recommendation.

I think cold start is pedal to the floor release and start with no pedal.

Hot start pedal half way down start with pedal half down...
 
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#16 ·
Mine can be quirky at times but I had to adjust the timing and fuel mixture on the carb to get an easier start on warm start ups. My engine is a 351W with a 670 street avenger carb that has an electronic choke, performer rpm heads/intake and a cam.

When its cold it takes three pumps but it fires right up after a second or two. When its warmed up I don't have to give it gas at all, it comes right on.
 
#17 ·
Did your carb have a choke on it? My dad has a 1969 roadrunner that had the original carb on it with no choke and it would do the same thing when it hadn't been started for awhile. For Christmas a couple years ago I bought him a Holley carb with electric choke and solved the problem. On my 1965 fastback it takes a little longer than normal for the car to get warmed up if it hasn't been started in a couple weeks but it starts right away with 3-5 pumps of the pedal and an electric choke
 
#19 ·
Whether my car sits for a week or a month...just a few quick taps on the pedal and it fires up as quickly as my 2005 F150. I do have electronic ignition which probably helps, but you shouldn't have to turn it over a lot. It should fire right up.

If it's been running awhile and I shut the car off and then start it again within 10 or 20 minutes, it does turn over more. Maybe turns over for 3-5 seconds. But to me, 5 seconds is a lot. I think this is probably because of some vapor lock or evaporation as the temps will rise underhood when the car has been running and is just shut off.


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#20 ·
Gas in a float bowl doesn't evaporate that fast. Gas in a clear inline filter can drain back to the fuel pump.

If your gas in the carb is disappearing in a Autolite carb then you have a porous casting or a loose top plate. In a Holley carb, or Holley knockoff like quickfuel it is probably slowly seeping thru the float bowl gaskets.

In any case, a well maintained carb will keep enough gas to fire the engine immediately, and even a month (and more) later. If it doesn't, it's needs attention.

Z
 
#21 ·
Gas in a float bowl doesn't evaporate that fast. Gas in a clear inline filter can drain back to the fuel pump.



If your gas in the carb is disappearing in a Autolite carb then you have a porous casting or a loose top plate. In a Holley carb, or Holley knockoff like quickfuel it is probably slowly seeping thru the float bowl gaskets.



In any case, a well maintained carb will keep enough gas to fire the engine immediately, and even a month (and more) later. If it doesn't, it's needs attention.



Z

But why would it take a few more turns during a hot start? I don't pump the accelerator if I had shut the car off within an hour or two.


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#22 ·
Hot starts are another matter, there are numerous factors at play. I was primarily addressing the main falsehood of this thread which seems to be the notion that it's normal for gas to evaporate out of a float bowl rapidly.

During a hot start, a car in good tune should start within a few seconds with the throttle held wide open, but not pumped repeatedly.


Z
 
#24 ·
First off the battery. Unless the car has an electrical problem (like a mild short) a good battery should hold near full charge for a month, cold or hot weather.

No comparison starting a recent (EFI) car or carbed car. The EFI vehicle is turn key or touch button and it's
running.

Cold engine with automatic choke floor and release gas pedal sets the choke. If the float bowel hasn't leaked down and the accelerator pump is working that first depression of the pedal also gives a shot of gas into the intake. In cold weather 2 or 3 added shots or more may be needed. Some get the idea that stomping on the gas pedal helps. Beats me why stomping would help!

Once the engine starts (cold start) there's a stepped cam in the choke linkage. It may take a minute depending on outside temp for the engine to warm up a little and drop the choke cam down to near normal
idle.

Note that round black plastic housing has a flat wound bi metal spring that opens the choke plate. It needs to be set properly.
 
#25 ·
+1 on setting the choke properly, it makes a considerable difference to cold starting! And proper dechoke clearance lets it keep running once it's first fired.
If your engine is warm, pumping it too much may cause it to begin to flood. Easy way to tell if you're doing that is when it does start when warm and you've hit the gas while cranking, do you see a puff of black smoke coming out the exhaust? Then you're engine's trying to start too rich- back off the throttle in your warm starting routine then. Also check timing, IIRC if timing is set too far advanced it's harder to start too.
 
#29 ·
E15 gas (summer blend) will percolate out of the float bowls of my Edelbrock 500cfm carb on top of my aluminum Edelbrock manifold with a fancy 1" spacer between to keep such from happening. You can hear it clearly after the car is shut off. Car runs at 180 degrees all day long. If you don't have to run the emissions blend gas you probably don't understand the problems of us that do. One of the reasons I'm installing the Fi-Tech EFI.
 
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#30 ·
You don't have to live with that. There are several bandaid fixes that can reduce if not eliminate heat soak carbs. I was plagued with that when I was running a set Weber 48 IDA carbs, but fixed it pretty easily.

What type of 1 inch spacer are you using ? Phenolic. ?

Have you installed an underhood aux. fan to reduce underhood temperatures ?

Have you installed an electric fuel pump ? ( you turn it off a few blocks before destination)

Edlebrock cars are worse for this than Holleys, I don't know why.


Any of these fixes are workable solutions, separately or in combination .

Z
 
#33 ·
Fuel injection will certainly fix the gas smell in your garage, as well as being the most expensive way to do so. From the description of the symptoms, Just sounds like a rebuilt Autolite carb, or a modern Holley is all you really need, but a little overkill never hurt anybody.

Z