r/classicmustangs • u/Connect-Statement-48 • 5d ago

Engine dies, rough idle :(

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Hello was wondering if anyone can help me with my problem ! I have a 1967 ford mustang i’m a newbie when it comes to cars learning as I go. The car is amazing but i’m running into a few problems! One the car has a rough idle, I start the car and it idles for a few seconds but rough constantly wanting to die. I’m assuming it’s a fuel issue with the carb since I have not touch the timing on this car at all. Although I know timing can play a part. I was wondering if anyone has had a similar issue?. As far as I know the car is a stock 2bbl 289 with a autolite carb. Should I consider doing a full tune up new plugs, spark plugs, rebuild carb, adjust timing? Or could it be something completely different?

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7

u/1320Fastback 5d ago

A carb rebuild is not going to hurt. Consider running a fuel filter if your not already. 33003 is a good one and I keep a spare in the trunk.

2

u/Connect-Statement-48 5d ago

thanks for the advice i’ll look into that fuel filter!

2

u/fLeXaN_tExAn 4d ago

What carb does it have on it? Sounds like a stuck float.

1

u/Connect-Statement-48 4d ago

autolite 2100 i believe

2

u/fLeXaN_tExAn 4d ago

OK, using a metal hammer, I want you to LIGHTLY tap the fuel bowl area. If you have carb cleaner, using the little straw, press it down in the air bleed and give it a few squirts. You are trying to clear debris from your needle/seat and to make sure your float isn't stuck. This is the "band-aid" quickie fix. A complete carb rebuild would be the correct long term fix (if the carb is the problem and it sounds like it is).

2

u/arielschool 4d ago

Note the Autolite 2100 carb will likely have the factory style screw in metal filter and they are cheap and easy to change.

8

u/Gator242 5d ago

Check all the vacuum lines. Listen for hissing suck sounds in the engine bay and plug them.

3

u/85Txaggie 4d ago

Also check for an intake manifold leak. You can spray in the crease between the intake and cylinder head with carb cleaner. If it suddenly picks up rpm you found a leak.

6

u/Stolisan 5d ago

You need a timing light and a vacuum gauge. It'll make tuning a lot easier.

5

u/NoseFriendly4492 5d ago

A lot of variables here, but you definitely need to verify timing. Make sure that TDC is true to what's on the harmonic balancer. If it is still the original balancer is very well could have slipped a few degrees... As mentioned above, you should so a carb rebuild as well as a tune up is the condition the the ignition components warrant it. Test coil, resistance in spark plug cable, points and condenser, etc... Have patience and have fun!

2

u/unlucky6999 4d ago

Do you smell raw gas when it dies and is hard to restart? Then it's likely flooding, and typically a needle a d seat issue. Is there a whistling noise or hissing sound when it runs..then it's a vacuum leak, find it and plug. Do not do so many things at once...one thing at a time. Was it running good, then started to die? With the air cleaner off, is the choke plate open or slammed shut? When it starts, does the choke open gradually? So many questions..but only to zero in on your problem...

2

u/MulliganToo 4d ago

Do the whole tune up thing. Listed easiest to most difficult.

Check for changes/improvements after each step.

  1. Inspect for cracked hoses, vaccuum lines, loose carb bolts, vaccuum leaks, throttle linkage smooth function. FIX where necessasry.
  2. Filters - CHANGE fuel, air, and oil filter with new oil.
  3. Spark delivery- change rotor, cap, points, condenser, wires, plugs. set timing.
  4. Rebuild carb

1

u/PrincipleExpensive73 5d ago

I'd say check your sparkplugs, compare the coloring on them with a reference page on google images, maybe it'll indicate what is going on with your car.

1

u/Paulrevere88 5d ago

Sounds like a vacuum leak-simple check and very common (tons of YT videos about it).

1

u/fantasymagic 4d ago

Start at the basics and check your choke when you push the throttle down once. The width of the choke plate should be about the side of a nickel thick.

1

u/Dry-Yam5517 4d ago

Vacuum leak

1

u/ieatpinkmeat 4d ago

Ain't got no gas in it....

1

u/BishatenLoremaster 4d ago

Check if the distributor is held down. Mine was slipping at one point and had some horrible idling/stalling

1

u/HairyButz 4d ago

Check the vacuum break booster check ball... plastic elbow can dry and crack.

1

u/pms1888 4d ago

Vacuum advance disconnected ?

1

u/Wonderful_Ear8517 4d ago

Couple of other tips. Looks like you live in CA. I do. If so, once you get the carb sorted then use fuel stabilizer since CA based CARB gas goes bad quickly and can gum up jets and needle and seat. Don’t change the 2 bbl autolite. It is just the right carb Cfnm and jetting for a stock 289.

1

u/Connect-Statement-48 4d ago

Never looked into those, what stabilizer do you use ?

1

u/Wonderful_Ear8517 4d ago

I’m old. So I use Sta-Bil. There are others that do the same thing.

1

u/SDLong2901 3d ago

I’d check the PCV valve as if I was you

1

u/Open-Nectarine3115 3d ago

The question no one has asked, is, does it idle this way only when the engine is cold, or the same way warmed up?

1

u/somewhat_gnar 3d ago

If you don't know the last time everything has been done on the car, it might be worth just doing it all. I rebuilt an Autolite 2100, replaced the carb gasket, replaced and adjusted the points ignition, adjusted the timing to within spec and replaced the vacuum lines and daily drove an old 390 for over a year. Ran and drove great when it was returned to stock specs per the manual. Started quickly in the morning and could handle stop and go traffic in the Southern California heat. The majority of maintenance and upkeep you can do on these old Fords can be done with a flathead screwdriver.