MBC75

I have a new crate engine installed in my car. 383 stroker with Edelbrock Performer 1411 750cfm carb and edelbrock intake, all of this was supplied by the engine builder. I am thrilled with the set up, runs great, lots of power very smooth. My only problem is hot starts, I have to crank it to death and really give it gas to get it started. When it is cold, two pumps of the pedal, hit the key, starts instantly. I called Edelbrock today and talked to a nice tech who said it was "Heat Soak" the manifold is transferring heat to the carb, in turn the fuel expands and dumps into the manifold causing a flooded condition. This explanation seemed plausible, regardless I have the hot start problem. He suggested a carb spacer that would help "insulate" the carb from the manifold. I don't have room for it to fit, I am already cutting it close for clearance. Is there anything else I can do ? Would changing to a double pumper style carb help with the problem, he indicated that it might help because the fuel would be in 2 separate bowls. Any suggestions are greatly appreciated.

7t9l82

a plastic spacer 1/2 in thick may work with a drop base air cleaner. i can't imagine a problem , i have an air gap manifold with a 750 double pumper 1/2 " spacer and a drop base and it all fits under my 79's hood

johnt365

I have had that issue in the past. Next time you get the car hot and turn it off, hang out and listen. You may be able to actually hear the fuel percolating and see it dripping down the throat. Here are some things that you can do that wont raise the carb any higher.

advanced timing runs cooler. How do you have your timing set now?
lower the float level. you may find a sweet spot that prevents boil over yet doesn't effect performance.
block off exhaust crossover port on intake manifold

My car is a small block, here in texas it is around 100* outside. I drove my car around this weekend for about an hour and a half and it stayed at 180* the whole time.

I have a .25 in spacer that I am using also. It may take a combination of modifications.

MBC75

That sounds good I will have to change my air cleaner, go with drop base to increase clearance, I will then be able to install the spacer. Are you also then suggesting going with a double pumper carb ?

MBC75

To be honest I would have to talk to my mechanic when it comes to timing, that is a little beyond me, that being said my car runs at 195-200 pretty much the entire time after it warms up. I am running a dual fan Dewitts radiator set up. Is this too hot ?

mac79vette

I have a suburban with a big block and a edelbrock carb.. I had the exact problem but found that if I lowered the float level just a little bit below what edelbrock recommends and it solved the problem, even in hot Texas heat. No spacer, but blocking off the exhaust passage in the intake manifold also helped quite a bit before I started messing with the float level.

worship79

Could this issue also be cause for dieseling after shut-off? I have the same carb and hot-start symptoms (and a 383).

CaseyJones

Very likely, in combination with other issues that plague our cars these day (cheap gas). Check your timing and make sure your mixture is not too lean otherwise. The plugs will tell the tale for you.

augiedoggy

Wood spacers are great for this... mines supposed to arrive from jegs today.
What I find interesting is the comment about the dual float bowls.... my edelbrock/carter 600 has dual float bowls.... so does yours, they just are side by side instead of front to back and they are further apart on a holly which isn't aluminium if I'm correct. This would make it slower at transferring heat.
They make 1/8" extra thick gasket spacers too.... you will want to try at least that.
I went with an intake that has no heat risers....this would be easier and cheaper to replace than the Carb in my opinion with just miner adjustments needed and no rejetting or brackets/fuel lines to change.
my dart heads also do not have the center heat riser.

1977L48

advance auto parts sells a thick gasket, like that found under q-jets but for a square bore carb, look up a gasket for a mopar big block and those came with carters on them and have the large gasket, they are about 1/4 inch to 3/8 inch thick

jcloving

I had the same problem with my stock '76 L-48. When I rebuilt the carb, I used a 0.25" phenolic spacer and that solved the problem. It was a spreadbore spacer, made for the Quadrajet.

Manuel Azevedo

Cheap Gas?? There is no such thing any more!!! Maybe low quality gas though!

noonie

AutoZone has these alum heat shields. Gasket above and below the aluminum.
Only adds less than 1/8" to stock setup.



Advance has a stainless shield, same setup

MBC75

Thanks for all the great suggestions, I am going to start with the spacer and see if this solves the problem.

biscuitville

I had a similar problem - get the car warmed up, turn it off, and it wouldn't start again cause all the fuel had left the carb bowls. I found some relief using the phenolic spacer. Someone else on this forum suggested installing a thin metal plate as is shown below. Since the install I haven't had any problems with percolation at all.
[IMG][/IMG]

Search the forum and I am sure you will find other pics of metal heat diverters that look much better than mine.

81$$pit

I had the same problem with 2 Edelbrock 600 carbs, added the wood type spacer from NAPA about $3 is all it was but still had issue with the needle sticking open and flooding issues. finally put a Holly 600 and problem went away.
Other things I have done since because still on a hot day it doesn't run 1/2 as good as a cold day is a 160 degree stat. fix all air dam and stuff around your radiator, buy a heat wrap for your gas lines, and yes timing. My car now runs at 160 even on a hot day and the oil temp doesnt go up past 200 or so. It used to go up to 260. If your oils that hot your engine comp is as well.