Edelbrock carburator/hard starting when warm

I just put an Edelbrock 600cfm carb on my 1959 Chrysler with a 383. The old carburetor was an AFB carter which is more or less the same carburetor.

The problem that I am having is starting the engine when it is warm. I am thinking that the heat from the motor is boiling the fuel out of the carburetor. The engine starts good when cold, when warm it will start o.k. if I start it up quickly after it is shut off but is hard to start if it sets for say 5 to 15 minutes. It then starts like it is flooded. Is this common with the Edelbrock carbs?

I had this carb on a 300 6 cylinder Ford in a pickup and it acted the same. The carburetor was new when I got it and ran it on the Ford for a couple years. The carter carb. that was on the car did the same thing, start hard when warm.

What can I do to get it starting better?

Thanks. Neal

 

Ya know I have the same problem with my Edlebrock 600. Starts hard when its warm and acts flooded. It seems as if the fuel is either boiling or sneaking passed the needle and seat and actaully flooding it. Haven't bothered to mess with it at all, just got used to it. I'm interested.

 

The aluminum heat sheild I put under the Edelbrock helped my car a lot ... ( see above )
On my roadster I even intalled a 1 inch spacer ... when helped a lot also.

.

 

I use a thick insulator type gasket and have not had this problem. I ran an Edelbrock for about 10 years on my truck and my son is using one on his.

Seems like I remember the instructions that came with the first carb recommended this gasket. Seems strange because the carbs come with a thin gasket.

Sorry, I don't have any part numbers. I usually just go to the parts house and look through their gaskets till I find what I want.

The one you want is about 3/8" thick and has plastic bushings in the bolt holes to prevent over tightening. I use the 4 hole gasket.

 

Thanks for the replies. I will look for an insulator to stick in there. Hope that does it. The carburetor runs real well otherwise.

Neal

 

I used a one inch spacer..problem solved

 

I have a similar problem. Yes the thing seems slow to start after warm-up but what I notice is that after sitting for 4 or 5 days it wont start at all until the fuel pump supplies fresh fuel. The gas is going somewhere however I remember reading somewhere that they were prone to leaking the fuel into the manifold. It had to do with a screw-in part poking through the casting but damned if I can remember the details.

 

There are some plugs on the bottom of the carb under the fuel bowls. One or more of them can be l leaking fuel into the manifold after you shut it down. After it sets a while and cools off some of it will evaporate and it wont be too rich to start. take the carb off right after you shut it down so the fuel bowls will be full and set on on the work bench on a rag and see if the rag has any gas in it after a few minutes. Also look into the manifold when you pull the carb off and see if raw fuel is in the plenum.

 

I'm doing fine with the roadsters 750 Edelbrock - and the 750 Carter before that along with the dual Carter 500's before those.
All on the same engine albeit with a cam swap here and there.

Both the 750's are on a 1" aluminum spacer/adapter and have an about 1/4" thick gasket between spacer and carb.

The dual 500's ran the 1/4" thick gaskets and that was it.

The engine lights right off hot or cold, but if it's been sitting a week or so it takes a little spinning of the starter to get gas into the float bowls.
If it's been driven in the last 2-3 days it lights off fine.

The 750's run an electric choke and as a small fwiw, the 500's had both manual chokes hooked up and operated from one cable although one would be sufficient.

I'd add a spacer as some of the guys suggested.
If you could find a block of phenolic you could make your own.

I don't know what the melting point of the UHMW (looks like Teflon, but tougher) is, I use the stuff for engine mount pads etc., but if it was high enough, making a spacer out of it would be quick and easy.
UHMW comes in various thicknesses.

I'd be inclined to give Deuce Roadster's good looking aluminum sheet metal shield a try.
18 gage? (Which is .063 thick if I remember right.)
Hard to believe the aluminum shields work so well, but they do.
Probably doesn't hurt that there's a gasket on both sides of the aluminum.
I'm guessing the aluminum shield also carries heat away from the carb and dissipates it to the air pretty much like a heat sink.
A good thing methinks.

You may want to check the carb's float height.
I hear that they've been coming through with the float height off a bit, but the ones I have - 3 bought new, one bought used (a week old) were right on the money.

Another thing you need to check is float drop.
If the float is allowed to drop too far the float's needle tab is pressing sideways against the needle instead of up and the needle stays open.
Had this happen to my 67 Barracuda coupe with a small AFB and it had the same starting problem you're having.
Set the float drop, end of problem.

One question; does the engine run a bit rough after a warm startup?
Not necessarily every time, but especially so after it's been hard to start.
Check your metering rods for straightness.
One of the aforementioned 500's had a slightly bent rod - from the factory - and it hung up one day.
It was wide open and the car wouldn't hardly run on the low end.
Got it home and the first rod I took out was bent.

Easy to check them for straight.
Remove them, separate piston from rod, let the short end of the "L" shape hang over your known to be flat piece - surface plate, piece of glass, machined steel flat surface - and roll the metering rod back and forth.
Any bends will be quickly evident.
Bend them straight with your fingers or if necessary use - gently - a pair of needlenose pliers.

Use care on the needle install, push the needle in gently with your finger and hold it in while you slide the plate over it and install the screw.
Take it easy on the screw torque, it's easy to overdo things.

Reason needles get bent is they go almost all the way in then hang up on the side of the main jet and sometimes excess force is applied.
Just work it around gently until it's centered in the main jet hole and you're in business.

 

Yeah! I thought that was shady too! I have to run an adapter to accomodate my spreadbore edelbrock manifold, and it spaces the carb up 1". I don't have any problems with the heat.

The little booklet they give you tells you to check the float adjustment, so that tells me that the factory isn't very confident about the way they are adjusted when they ship. Lots of guys have trouble with them. I adjusted mine just to be safe, but it was real close out of the box.

 

Might want to do something to block off the heat risers under the carb. I never understood why we left those things open-putting hot exhaust gas under the carb might SEEM like a good idea, but kind of goes against the whole Avagadro's law about gasses under pressure. Or was it Bernoulli's Principle? I lost track....

 

Ooops, Sorry. I just checked. It was Boyle's law.

 

I can't speak for the edelbrocks but the Carters and the Rochester 4 bbls have a set of welch plugs in the bottom of the bowls which are leakage-prone. On the last Carter I rebuilt (a WCFB) I drilled and tapped the plug holes to accept a socket-head setscrew, and sealed them in place with a dab of JB weld on the threads. Do this from the UNDERSIDE of the bowl - separating the carb body from the throttle body so as not to bung up the inside of the bowl.

 

You live in LA - that explains it...

In areas of the country where it ain't 83 and sunny 10 months of the year, fuel has a nasty habit of dropping out of its atomized state between the venturi and the combustion chamber, resulting in a lean mix and uneven combustion. Preheating the A/F mix keeps it in suspension, thus improving driveability during the warm-up cycle - and in cold climates, eliminates carburetor icing.

 

Verify your timing is set correctly and make sure your ignition is up to snuff. Since you've had the same problem with two different carbs, maybe its not the carbs.

The Edlebrock carbs do not like a lot of fuel pressure. 5-1/2lbs seems to be what they like. More than that can cause residual pressure in the system to push fuel past the inlet needle and flood the motor after shutdown. Another common problem with the Edelbrock carbs is the tendency to wear out the viton inlet needle. Pull the carb top and check the inlet needle for wear. A small groove in the tapered portion of the needle where it seats is a probable cause. While the carb top is off verify that the float level is set at 7/16". Check with your specific carb's owners manual that you got with the carb or check on Edelbrocks site or tech line for actual specs for your model.....but I'm pretty sure most of them are 7/16".

Good luck with it.

-Bigchief.

 

Next time you go to start it when warm, rest your foot w/ SLIGHT PRESSURE on the accelerator pedal. Works every time for me- give it a try -Betruger-

 

Might 'splain the discoloration of all the aluminum manifolds I've ever used under 'em -Betruger-

 

That works, its what I do. But thats not a solution. Seems as if a plastic or aluminum spacer should do the trick to cure all ails. Didn't think it was as simple as that, but alas, I am enlightened.