Car starts great when cold (as in reach-through-the-window good -- no pumping the gas pedal, no hard cranking etc.

...but, if I need to restart once the engine is hot (like running errands) it will crank and crank and crank and I have to pump the gas pedal like crazy to get it to fire up, and even then it wants to sputter and die, so I have to two-foot it until I've had a chance to get it up to speed again (then it will behave as normal)

A little background info
Car is 1970 Cutlass S 350ci
Edelbrock 1407 carb (750cfm)
Recent (within last 100 miles) tune-up included new fuel filter

Is this a carb-tuning issue? Too lean maybe?
Or a fuel delivery issue?

 

Are you using the mechanical choke? What is your tune set to?

 

Why do you say lean? new plugs/check them? More info please
Doubt it's lean unless its a choke problem or new filter is clogged already. heat soaked maybe or stuck needle valve,float level low/high my the list goes on.... Try not pumping it and just hold it open when hot and see if it starts up, you may be flooding an already flooded engine.

 

I don't know The Edelbrock was already on the car when I bought it & I haven't messed with it... I guess that's why I'm asking if that's a possible solution for these symptoms

I thought lean because it seems like its not getting enough fuel...?
tune up did also included new plugs/wires, (and distributor cap/rotor, battery + cable terminals, air filter)

It will occasionally catch without pumping the gas, but not until after MUCH cranking and even then it sounds like an old tractor or something and wants to die until I give it some gas

Edit: fuel filter is the clear window style & I can see it's still immaculate!

 

I should mention - most of the above ^ pertains to car still in Park...

When I start to drive it (R or D), I actually have to feather the gas - if I give it too much it will die

Also, just in case it's related, the car does have intermittent mild hesitation issues, both under normal acceleration and WOT

Reiterate - none of these symptoms exist on cold start up

 

If you take your air cleaner of and look at the opening of the carburetor is the choke butterfly open all the way? It will be perpendicular to the manifold. Also while your looking down there, if you manually move the throttle, do you see 2 jets of fuel sprayed in there?

Is there a cable going from under your dash to the passenger side of the carb?

 

Do you have one of Edelbrock insulator gaskets on the car? It's a 3/8 gasket to lower the temp of the carb, preventing the fuel from boiling. Mine improved some after I installed the gasket.

Relating to the hesitation, could the 750cfm just be too big for the 350ci motor? when it's cold, it's going to idle higher and such, using more fuel.

 

I had the same problems with an Edelbrock 750/1407 on my 455. Also on a 396 chebb. Changed rods etc with their tune kit. No difference on either. Gave up on them. Next was Holly street avenger. Ok but could not tune the rich idle out of it as is known with them. Now I am running a 800cfm quadrajet built to my engine and drivetrain specs. Thing has been great for 2 years now. Same if not better performance. These are good carbs!

 

Well, uh, could this be a contributing factor?





The choke isn't hooked up to anything so it's just always open!

Is there somewhere to buy the little linkage rod? I checked evilbay and summit but no luck, just rebuild kits & linkage kits (for setting up dual or triple carb setups)

 

Never mind I think I found one

 

Uh yah!

 

That's an accelerator pump kit not choke.

 

You need the entire choke.

 

Yes, that's your problem. It's made for a manual choke cable. What I would do is wire it open for now. That will prevent it from closing on it's own. Also make sure that your throttle is opening all the way when the gas pedal is pressed to the floor. Adjust your linkage accordingly.

 

You can't really tell from the pictures, but it's actually the opposite -- it's always open (straight up & down)

 

Yup, you're right

Now I'm stuck again, the only choke kit I can find is for the electronic choke whereas mine's the old manual style (which I would prefer to stick with)

 

It looked like it was closed in the picture. If it was open then it is not your problem. It does look like your carb to manifold gasket may be torn. Is it ok and are the bolts tight?

When you operate the throttle manually with the engine off looking into the carb, are there 2 good streams spraying in there?

 

Wow
That's a lot of work to fork up a perfectly good well engineered factory system.

How about putting a well built QJet on there with the AUTOMATIC choke that works really well?

Just a thought.

 

Yep, kind of what I was getting at. My Quadrajet has an electric choke. 1 wire, hook it up and forget it. And fast idle cold functions work great.

 

Yes two good squirters

If the carb was set to start cold with the open choke, could it actually be flooded on a hot start delivering similar symptoms?
I read somewhere that there's a difference between pumping the accelerator when cranking and holding it to the floor which actually clears out the fuel...?
So today I tried that several time sand it starts much better than pumping

 

It may also be your timing may be off, what distributor are you running and do you know what it's set to? Sometimes ignition issues seem like carb issues.

 

It's an HEI distributor... but I have no idea what the timing is at (or how to check it or adjust it)

I will have to check on that gasket tomorrow

As to the quadrajet, I'm not at all opposed to switching carbs, just figured I'd try to work with what I got first

 

Who did your tune up? The carb you have ought to work fine. Sometimes you don't need to pump the gas on a warm engine to start it. You can try turning the key and while its cranking depress the gas halfway and see what happens.

 

If the carb was set to start cold with the open choke, could it actually be flooded on a hot start delivering similar symptoms?
YES!
I read somewhere that there's a difference between pumping the accelerator when cranking and holding it to the floor which actually clears out the fuel...?

pumping will keep adding fuel to and already flooded engine. holding it open will only pump the squirters once.

So today I tried that several time sand it starts much better than pumping
about time

 

Man, last week I went to start my car and it was flooded. It turns out that my 11 year old and her friend were playing in the car and pressed the pedal a lot of time's during their fun. Well, I went to start her and she kept sputtering at first. So I did the floor it method to start a flooded engine . Wrong! Once it fired on a cold engine it went to 4 or 5 grand instantly!
Won't do that one again. Oh, and a lot of smoke out of the tailpipes. Anyways, it's fine. Whew!

 

So I downloaded an Edelbrock owner's manual yesterday and set about trying to dial in the carburetor. It was starting much better when hot, and idling better in traffic, but much rougher now this morning on a cold start (which I guess is to be expected with the choke not being hooked up )

So, I either need to fix the choke (still haven't found a proper kit btw) or, as some have suggested, would I be better off in the long run just buying myself a rebuilt quadrajet?
The car also currently has an Edelbrock Performer RPM intake which I'm told is about 2" taller than the stock manifold - how does the q-jet stack up size wise to the Edelbrock carb? Would it still fit under the hood?

 

holding it open will only pump the squirters once.
======================
That, plus the feature called the CHOKE UNLOADER which props the choke open quite a bit, like it or not, at WOT, in order to address this exact issue.

I recommend that folks spend one evening reading thru the service manual coverage of the 6 basic carb systems- purpose and implementation- and examining these systems on a carb similar to what their car uses. The basic section in a Chilton's may be adequate, or the Chassis Service Manual is another good choice. Nothing like hands-on time with a spare/ scrap carb though.

 

Yeah, +1 on all of that.

It seems as though some extremely basic knowledge has been essentially lost over the past few years, things like "Don't pump it - you'll flood it!" and "Just hold it open and crank it to clear it."

I would add to the resource list quoted above, the Rochester QuadraJet Manual, which contains much the same information that is included in the Carburetor section of most Chassis Service Manuals.

- Eric

 

Considering I didn't turn 16 until 2001... yeah carburetors aren't exactly part of my generation's repertoire lol.
But I freely admit my ignorance & will look into picking up some of the above resources

 

Yeah, nothing personal, but if you grew up having heard certain things repeated over and over by different people, from as early as you could remember, things such as the quotes I posted above, and such as "Don't scratch, it'll get infected," and "Over 60mph, you're not driving it, you're aiming it," you'd see how surreal it is for some of us to see people who have somehow grown to maturity never having absorbed this knowledge.

People born in the 19th century must have had the same feeling when they encountered people who could drive a car but not a team.

- Eric

 

All you need is a cable, or convert yours to an electric choke. Adjusting the air/fuel mixture screws on a cold engine will only screw up your idle when it gets warm.

 

Now that we got that sorted out. You'll have to adjust the idle. As of right now it's probably way up there if you can start it cold without having to hold the gas down to keep it running. And if it's heat soaked seeing as the choke is wide open when hot and you need to clear it still to start. Don't feel bad coldfire I'm 28 and was just lucky enough to grow up in a garage.

 

Exactly. However my daughter pumped it countless times before I tried to start her. 1st time in 4 years that this car did this. And hasn't since. After about 3 times sputtering, I put it to the floor and all hell broke loose for a cold engine. Anyways, right or wrong, we will not be doing this again. I usually just tap the pedal to set the choke and fast idle. Other than this, it's always been right on.