Need advice from the mechanic knowledgeable…

[Fisherj14]

I recently bought a FFR Cobra with a 347 small block in it. When I crank this thing, I really have to give it a lot of gas or dies over an over again until it has enough gas primed in the engine. Then, when I start driving, there can be a lot of stuttering between gears. I’ve added some fuel injector cleaner to the latest tank of gas but I haven’t seen a big improvement. You guys got any opinions on what I need to do to make this engine crank easier and run smoother without all of the stuttering? Thanks guys!

[cv2065]

You said you added fuel injector cleaner. Are you sure that its fuel injected or carbureted? If indeed FI, what kind of system are you running? Might help the gurus diagnose your issue better to know the hardware you are running.

[Fisherj14]

I will let you know that I know as much about cars as I know about women…not much. So, I’ll just list what was in the ad:

1965 FFR Shelby Cobra.347 ci blue print with world class, 5 speed transmission, disc brake in the front and drums on back.
15” tires 225/60 R15 in the front and 275/50/R15 in the rear.
Tires brand is BF Good Rich.
1990 Mustang differential and fuel tank, electronic fuel pump, manual electric fan,
1990 Mustang radiator, double pumper Holley carburetor, 4 point raising seat belt,

[cv2065]

Sounds like its carbureted, but maybe take a few pictures of the top end to be sure. Might want to start with the simple stuff like timing. If you aren't sure about that, maybe if the forum knows what area you are in, someone local might be able to assist.

[Mastertech5]

Is the shuddering from the engine surging or from the clutch. You said between shifts. Tuning a carb is an art form to get it perfect. Most of the guys I use to work with have never worked on one. You have to be able to "read" the spark plugs to tune it right. Example: jet size, air bleed size and idle air adjustment. Does the choke work? These affect the air/fuel ratio which is critical for the engine to run correctly. Different makes of carbs can have different ways to adjust these things. Taking it to a performance shop is probably your best bet unless you know someone like cv2065 said.

[Fisherj14]

Thanks guys. I wish I could be more help. I only know that when I crank it without depressing the pedal before doing so from a cold start, it will just try and turn over but never will. If I give it some gas and crank it again, it will start but will usually shut back off. I’ll depress the gas again and it will usually crank this time. Then I rev it a couple of times to get it going. But, when I put it in reverse and start backwards, if I don’t really give it a lot of gas, it will cut back off again. I’ll give it one last gas push and then it will crank up and let me at least back out. For the first couple of gears after that, it will stutter pretty bad until she gets warmed up and then we are good. We will repeat this exercise every day that I try and drive it.

[Gilmore]

Sounds like the choke isn't being used or isn't working if electric.

[edwardb]

We've gotten spoiled with modern engines and fuel injection... Totally normal for a carb'd car to require several pumps of the accelerator to the floor before cranking when cold, e.g. the first start of the day. Primes the engine plus closes the choke if it has one and it's working. If you don't, no surprise it cranks longer than it should and dies after starting. Also not unusual to require a minute or two of fast idle to get warmed up enough to run reliably. Some carbs have a choke, usually electric, and agree it might not be working properly. But many performance carbs don't have a choke or the owner/builder/tuner removes them. Try the start process as I described and let it warm up some before driving. Let us know if things are any different. If it's been sitting for awhile, injection cleaner might help to clear out the carb. Can't hurt. Old gas also can cause problems.

[GoDadGo]

We've gotten spoiled with modern engines and fuel injection.

Amen Sir Paul, Amen!

I have a routine that I use and it works fine which is listed below:


I push the car out of the shop & then put in my earplugs. (My Car Is Crazy Loud)
I get in and crank the Redbone Roadster around 5-7 seconds to make sure the fuel bowls are filled.
After that I pump it 3-5 times depending on how cool it is outside. (Cooler Weather Gets More Pumps)
I then wait 7-10 seconds before cranking it again and it fires right up.
Finally, I let the car warm up while I put my seat belts on & then I'm Good-2-Geaux!

It brings me back to days gone by when I owned a 1969 Chevy Truck.

We Truly Forgot Those Old Carbureted Starting Tactics!

[Fisherj14]

Thanks guys. I wasn’t sure if it was normal or not. I’m 46 and remember my first car (84 Firebird) needing to be warmed up but didn’t know if that was specific to the car or engines of the day.

I also got some Octane booster to throw in it to see if that helps as well. I live in a quiet golf course neighborhood down quite possibly the quietest street inside and I can tell you one thing….the male neighbors have all come to look at the Cobra and love it. The females not so much. When I got in yesterday morning to drop her off for an oil change and revved her several times to get going, I saw my neighbor next door bringing his trash out. He said, “man I love the sound of that thing. My wife, was just woken up by it so she is not as thrilled.”

[CaptB]

If you have the means get a Sniper, your life will get signficantly better.

[CraigS]

If all is correctly adjusted w/ the carb and it's choke follow this procedure for a cold start. Push gas to the floor, hold it there for a couple of seconds, then release it. This does a few things. 1- It gives the choke time to close and 2- the high idle cam to move under the throttle linkage, 3- squirts some gas into the carb. Now the engine should fire up and idle at 1000-1500 by itself. If it doesn't keep running, shut it off and do the process again but push the gas down twice. #1 and #2 will be the same but #3 will get a double shot of gas squirted. This is all normal for an old school carbed engine. If your engine doesn't work this way, there are some adjustments that need to be made. The first step if it doesn't work is pull the air cleaner off and look at the choke plate. This is an old carb w/ the choke open or
off'.
https://www.grantmaclaren.com/72skier/carburetor/index3_04.jpg
This is a choke closed or 'on'. Ignore the labels about the choke cable.
https://ww2.justanswer.com/uploads/sgm11155/2011-10-29_200149_10-29-2011_12-59-23_pm.png
Let us know what you see and we can go from there.

[gbranham]

Congrats on the purchase. I will say that buying someone else's project car isn't for the mechanically un-inclined...if you didn't know it was carbureted despite the ad saying it had a Holley carburetor, you're in for a steep learning curve. This forum can really help you for sure, but you're going to have to learn some basic car mechanics to truly enjoy it.

[Scott L]

Congratulations. There is a learning curve but it is worth it. Try to find a local cruise night or cars and coffee. Talk to owners about who they use and recommend. You should be able to find a local shop that is not afraid of a carburetor. Good luck.

[Fisherj14]

Thanks guys and yes, absolutely understand I have a learning curve in front of me. There is a guy in town that has an original Cobra that works on them that I just found out about today. He said to bring it to him and he’ll walk me through an engine 101 session to help me understand the car more. He is really looking forward to seeing it and just loves old cars. Thanks for all the responses guys!

[kirby]

That is awesome. Nobody started out having knowledge on cars it's something that gets built over the years and through experience. Having good contacts is a huge help. Keep the guys number, find out what he likes to drink, eat etc and treat him to it.

[Ford & Jeep Fan]

Here is the reason carbs can be so unpredictable to many people.
At full operating temp(180'F-205'F) a engine needs ABOUT 14.7 to 1 Air to fuel Ratio.
At -40'F You need about 2 or 3 to 1 and as it runs and warms It slowly heads towards that 14.7 to 1.
EFI does all the calculations in a split second. AS long as all sensors work properly,are grounded propely,..... You get the idea.
I likke my EFI on my daily driver. But like the Carbs for high perfomance work.

[Inman Lanier]

FisherJ14 - a simple inspection will confirm some of the above suspicions.

I would start by the following. With the engine cold, remove the air cleaner / cover. Look down inside (take a picture is even better). THEN (not first but after the photo), do the single throttle depress to the floor, hold for a second or 2 then go back and look. I'm with some of the others - you either don't have a choke, or it is maladjusted (or if manual, you're not pulling the knob on the cable). The difference before and after will be in the first look down, you'll see 4 holes arranged like a rectangle. The top of the front holes will be unobstructed. After pressing the throttle the plate on a hinge in the top of the front holes should now close a good bit.

That's a choke. In the below photos (your carb may look different), the bottom ports in the photo are your two 'primary' venturi. They are what get choked. Notice in the before photo the blade on top is vertical, not blocking (i.e. choking) the flow. In the after photo, this is what happens with a cold engine where the choke automatically engages. The choke plate has rotated to a horizontal plane, 'choking' the primary venturi. This means now when the engine cranks, it draws a lot more fuel through the jets in the carb and makes it more 'rich' - needed when an engine is cold.

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Let us know (again - photos best) what you see.