Cleveland + Edelbrock Carby hard to start when hot ??

[Platinum Blue 12]

This sounds too simple , !!  Heat insulation plate ?

 

Starts on the first rev when dead cold, but cranks as if its flooded when hot or even 5 Hours after running ??

Foot on Floor will get it started, but loads of fuel.

 

Engine is new rebuild and new 4Barrel Edelbrock  carby,  Runs fine otherwise.

 

Is there another solution ??      

[slydog 7,873]

Only Bear knows Edelbrock carbys around here...

[Anthony Pllu 262]

mine is the opposite wont run unless your on the throttle when its cold

[gerg 10,871]

Same problem as my aluminium Holley. It's a combination of hot engine bay, ally carby and shit fuel these days.

 

These 3 factors all contribute to this problem, this is why:

 

XD-XF bonnets are low and the engine bays are cramped so heat has trouble escaping, particularly if the car is left sitting there for say 15 min.

 

The aluminium body of the carby conducts heat much better than the die-cast zinc Holleys, so the fuel heats up more in the bowls and emulsion wells.

 

Lastly, fuel these days (especially E10) is much more volatile than that of years ago, ie evaporates at much lower temperature. Not a drama in 99% of cars on the road as they are fuel-injected (under pressure). Carby cars have the fuel sit at atmospheric pressure in the bowls.

 

Here's how it all happens:

 

As the car sits there turned off, your carby becomes a very expensive and complex saucepan sitting on top of a very expensive and complex stove (your engine). Fuel boils in all of the circuits (including your acc pump) but particularly in your emulsion tubes. This happens more here because the engine is drawing vacuum through them so the fuel boils even more easily.

 

So instead of liquid fuel being mixed with air inside the emulsion tubes, (normal) you have fuel plus a certain amount of vapour mixing with air (not normal). This is way too lean to start the engine properly. This is your situation, and it's called "vapour lock". Sometimes even pumping the throttle doesn't work because the fuel's boiled out of the acc pump circuit too.

 

There are some things that you can do to help stop this.

 

* Adjust your bonnet hinges so the back of the bonnet has a larger gap to let heat out. Looks a bit ghetto though. Alternately, you could fit a cowl or bonnet vents.

 

* Get yourself a carby insulating spacer... Again the bonnet clearance is an issue. I used a GM Rochester type that's 1/4" thick. Probly does fuck all but better than nothing. I personally think the problem isn't so much conduction through the manifold but ambient under-bonnet heat.

 

* Drop-base air cleaners tend to catch heat like a giant upside-down funnel too. I went with this type instead:

 

 

* If you don't already use premium 98, do so. It seems to have less problem with boiling.

 

Even after all this stuffing around, i find that i still have to live with hard starting when hot. It's just a fact of life these days.

 

An Edelbrock air gap would work in your favour as they have no exhaust crossover (my stocker iron one does).

[gerg 10,871]

mine is the opposite wont run unless your on the throttle when its cold

 

Is your choke adjusted right?

[Thom 6,654]

Only Bear knows Edelbrock carbys around here...

 

I use them too

 

 

 

 

I used to have this issue in my customline, it turned out to have a few contributing factors, first I'd check your float levels I've pulled a few of these apart and they are rarely right out of the box, do you have a fuel pressure regulator? If not fit one and a new needle and seat while you are at it (edelbrocks only need 3-4 psi any more and you will push fuel past the needle and seat, even a stock mechanical fuel pump can pump beyond that, this over fills the float bowl when the engine is shut off and dumps excess fuel into the carb) also and insulator could help if you have the room for one

[slydog 7,873]

LOL nah just having a joke with Bear bro...he likes these carbs and I thought maybe he could help. Looks like you boys have it covered though.

[bear351c 10,273]

Yeap, all of the above.  Onya Sly.....

[slydog 7,873]

Thought you would like that one bro...LOL

 

Have to say I think Gerg is in the wrong profession though...holy shit he has not only the problem but the repair and explanation down too...as doe's Thom but he's a Mexican and he can just stay playing with trains or whatever makes him so dirty in his day to day travels.

 

Outstanding contributors...

[Thom 6,654]

Thought you would like that one bro...LOL

 

Have to say I think Gerg is in the wrong profession though...holy shit he has not only the problem but the repair and explanation down too...as doe's Thom but he's a Mexican and he can just stay playing with trains or whatever makes him so dirty in his day to day travels.

 

Outstanding contributors...

 

You're just jealous of my train set

[Platinum Blue 12]

Ahhh not so simple , Thanks for the insights !!

 

Petrol sniffing is OK for your health , isn't it ?  

[bear351c 10,273]

Sure is.

 

Everything in moderation.