More Edelbrock Hot Hard Starting Problems

Sorry for such a long post. I'll keep it as short as I can. I've got at fresh rebuilt 327 with PBM Thunder heads (World Products S/R), Performer intake, and an Edelbrock 1405 600cfm carb. I'm running an L79 pcv system. The engine runs great but I've got the typical problem that many others have with the car not wanting to start after getting it hot and trying to crank it after sitting for 10 or 15 minutes. Of course it's flooding due to boiling fuel. I've tried one of their 1/2" wooden spacers, then a 1" phenolic spacer, and now one of their insulator gaskets but without spacers. Nothing has worked so far. When it does this the only way to crank it is to mash the pedal to the floor to clear it out. If you have just drove it about 30 or 40 miles on a hot day like today it's really bad. I like the carb and it does great other than this. Good acceleration and plenty of kick but I've got to do something. I didn't put the block off plates in the intake gaskets when I put the motor together, which I know would help but at one time I thought I was going to run a Quadrajet that I have so I would need those unblocked for the choke unit in the intake. I really hate to have to pull the intake to do this since I'll have to get the a/c compressor out of the way and take the bracket off to do it and I'm not sure that would cure it. I understand part of it is the Ethanol in the gas we use these days. I would change carbs and go with a Holley Street Avenger or send my Quadrajet off for rebuild and tuning by Sean Murphy if I knew they wouldn't have the problem. Can anyone here that's had this issue tell me if they switched to a Holley or Quadrajet and cured this problem? Is a Quadrajet prone to suffer from this? I've never heard of them having these issues but I don't know. I see so many Edelbrocks at car shows I go to as I did today. I saw a bunch of them and 90% of them had no spacer or insulator gasket. I like them and they are easy to work on but I've had it. Any ideas, opinions, or suggestions are welcome.

its not the carb... it is heat ....try a alum heat sheild under the carb and use a wood or phenolic . make sure your only making 5 psi with the pump. check floats maybe to hi set them abit lower. check fuel lines that are away from heat source

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Originally Posted by pat mccarthy

its not the carb... it is heat ....try a alum heat sheild under the carb and use a wood or phenolic . make sure your only making 5 psi with the pump. check floats maybe to hi set them abit lower. check fuel lines that are away from heat source

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I'm running a stock fuel pump and I have the fuel filter away from the engine I'm using a rubber line. I took the carb apart earlier this week and checked the float levels. The book says 7/16" between the top of float and top of carb and 15/16" to 1" drop. They measure 7/16" and 15/16" drop so you are saying I can have them drop lower and it might help? Thanks for the suggestions.

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Originally Posted by tidefan66

I'm running a stock fuel pump and I have the fuel filter away from the engine I'm using a rubber line. I took the carb apart earlier this week and checked the float levels. The book says 7/16" between the top of float and top of carb and 15/16" to 1" drop. They measure 7/16" and 15/16" drop so you are saying I can have them drop lower and it might help? Thanks for the suggestions.

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try it if it will not help set them back to stock spec is the carb flooding when hot car stops running or just not restart after getting hot ? what is hot ? what is your temp?

Restarting after sitting for 10 or 15 minutes and temperature is 180 down the road, 190 at idle or in traffic. Less if weather is cooler. I have a 4 row brass/copper radiator, high flow water pump, clutch fan and radiator shroud.

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Originally Posted by tidefan66

I'm running a stock fuel pump and I have the fuel filter away from the engine I'm using a rubber line. I took the carb apart earlier this week and checked the float levels. The book says 7/16" between the top of float and top of carb and 15/16" to 1" drop. They measure 7/16" and 15/16" drop so you are saying I can have them drop lower and it might help? Thanks for the suggestions.

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Tidefan66,
When Pat says to drop the level a bit he's referring to the top of float/top of carb measurement (7/16") not your drop measurement. That TOF/TOC sets the fuel level in the bowl, and the idea is that a slightly reduced level might help. What vehicle is this in? Wonder if you've done anything that's trapping the heat under the hood with no place to go? Just a thought... I believe the insulating spacer beneath the carb is a good thing to keep, and if you can find an area station that does not add ethanol it would be a good test of that theory to run the tank nearly dry, then add five gallons or so of known good gas. One other thought, a friend told me a few days ago that he notices a big difference in starting by adding the prescribed amount of STABIL to his gas, even in hot weather - can't swear to that, but might be worth a try?

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Originally Posted by rspears

Tidefan66,
When Pat says to drop the level a bit he's referring to the top of float/top of carb measurement (7/16") not your drop measurement. That TOF/TOC sets the fuel level in the bowl, and the idea is that a slightly reduced level might help. What vehicle is this in? Wonder if you've done anything that's trapping the heat under the hood with no place to go? Just a thought... I believe the insulating spacer beneath the carb is a good thing to keep, and if you can find an area station that does not add ethanol it would be a good test of that theory to run the tank nearly dry, then add five gallons or so of known good gas. One other thought, a friend told me a few days ago that he notices a big difference in starting by adding the prescribed amount of STABIL to his gas, even in hot weather - can't swear to that, but might be worth a try?

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It's in a 66 Chevy II. I had a 350 in it with the same carb but over the winter I built this 327 since that's what I wanted in the first place. I had some hard starting issues when the carb was on that engine but I put a 1/2" wood spacer between the carb and intake and it solved the problem. It's been so long since I built the 350 but I may have put the block off plates in the intake gaskets on that one. I'm sure it would help but it's a lot of trouble to take the intake off. I'll drop the float level a little and I may put the 1/2" spacer on top of the insulator gasket as well. I would like to keep this carb if possible but if I was pretty sure a Holley or Quadrajet would work better I would swap in a second. We do have some stations here and there that sell non ethanol gas so I may try that. I'm thinking the Quadrajet is a way to go since they originally worked with the passage open under the intake on count of the choke. Stabil might be worth a shot too. I know I'm tired of working on it. I like to work on these old cars but I don't like having to deal with the same problem over and over. Right now I just want to enjoy it.

When your talking about it starting hard, is your starter turning the motor over easy? Heat shield between the starter and block. I had that issue before.

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Originally Posted by Trjohn57

When your talking about it starting hard, is your starter turning the motor over easy? Heat shield between the starter and block. I had that issue before.

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Yes it is. It's a mini starter.

I changed the float level from 7/16" to 1/2" but now it doesn't want to idle at all or run very good. Did I go too much or the wrong way?

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Originally Posted by tidefan66

I changed the float level from 7/16" to 1/2" but now it doesn't want to idle at all or run very good. Did I go too much or the wrong way?

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You went the right way, increasing the delta which drops the level. However, the float level is what establishes the static head on the jets, and it sounds like your engine is very sensitive to that static head. You might be able to rejet the mains and adjust your idle mixture to account for the lower level, but it's going to be some hassles. If it were mine I would put it back at 7/16" and chase the heat problem. Do you have room to put on a metal heat shield beneath the carb that extends out and up from the manifold to reflect the heat away from the carb body?

Well I'm ready to chunk the Edelbrock. I just don't know whether to have my Quadrajet rebuilt and tuned or buy a Street Avenger. Any thoughts?

Buy the Holley. Had the same problems. To much heat under the hood. Motor to hot. The Holley works fine. Gave the edelbrock to a guy with a 289 in a T-Bucket and it works fine.

i`ve had 750 holleys on everything from 289`s to 460`s .. worked well on all .. i`ve an edlebrock on my V6 pinto now .. it is hard to start when hot also .. you remember old chryslers had vapor lock and hard start problems years ago with the afb carbs ..

well thats funny i have afbs on some blower cars and they do run warm allways start up

not much heat soak with a blower ..

you better re think that a one you want to put your hand on my blower when block coolant temp reads 220? that one big chunk of alum and get vey hot as it is bolted to the engine block

Well this Edelbrock carb has got to go but I have to decide what to go with. I did what was suggested by someone on another forum and by Edelbrock and set the float level to 1/2" instead of 7/16" which mine were less than that. It made no difference at all. It's getting worse about flooding in that once you get it started it doesn't want to run until you get it out on the road and clear it up. I also checked to see if I had installed the block off plates in the intake gaskets on the 350 I was running with the same carburetor since I couldn't remember. Well I didn't put them in that engine either and it never flooded like this. It would be hard to start after it got hot but a 1/2" wooden spacer cured it. Nothing works on this engine. So, I'm going to have this Quadrajet I have reworked or go with a Holley of some kind.

I agree with Pat, the Edelbrocks are generally very forgiving carbs. As for heat, I ran one on my Jeep truck (5.0 Ford engine) and it got very hot under the hood here in Florida. Never had one issue. The only time I ever saw an Edelbrock perk the fuel was one day Don and I took our cars on a long trip, on a hot day, and his carb bases got so hot that it started running badly. When it cooled down it was fine from then on. I think we are going to add carb spacers to prevent that from happening again, if it ever does.

Why don't you call Edelbrock and run it by one of their tech guys. I've called them a few times for help on stuff and they have always been helpful.

Don

Tidefan,
Was this a new carb with the fresh rebuild, or a carb that had been used before? Did you buy the carb new? If used has it been rebuilt? Just wondering because I read back through the whole thread it seems possible that there is simply something leaking with this particular carb, especially when you say it's getting worse with time.

Go with the Quadrajet, Edelbrocks seem to be forgiving, but getting them set correctly for the engine/conditions has been a tough nut for me to crack!:o Even after installing a re-build kit!:eek:

I understand that you need to pay attention to mounting of the carb to the intake manifold, I have an edelbrock manifold and it seems that I need to get some type of conversion plate to accept the Quad...:confused:

Good luck! and be sure to let us know how it turns out!

In my experience when ever the float setting was adjusted it would effect the float drop adjustment and it became a constant back and forth battle. One of the reason I went with Holley

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Originally Posted by rspears

Tidefan,
Was this a new carb with the fresh rebuild, or a carb that had been used before? Did you buy the carb new? If used has it been rebuilt? Just wondering because I read back through the whole thread it seems possible that there is simply something leaking with this particular carb, especially when you say it's getting worse with time.

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This was one of Edelbrock's factory reman. carburetors and I bought it from Summit. It looked like a brand new one when I took it out of the box. Like I said earlier, it didn't flood like this when I had it on my 350 and I was using a 1/2" wood spacer. It would start pretty easy when hot but on this engine it's terrible. I'm sure the block off plates would help some but I doubt it would eliminate the problem as bad as it is. I'm going to contact Edelbrock tomorrow but I am not very optimistic. I've got a 1/4" base gasket ordered for my Quadrajet and Saturday I'm going to put it on there and see how it reacts. It's been sitting up in a box for a while but maybe it will run enough to test it out. If it works I'll send it to Sean Murphy or All American Carburetor and let them work their magic. The only thing with a vacuum secondary Holley is people will say they don't have as much kick with the secondaries. That they come in gradually. I've never run one personally but my dad has an 1850 600 cfm on a 350 SBC and he put one of those kits to convert from a rear metering plate to the metering block with jets. It runs good and is very reliable but the secondaries don't kick in very hard. He hates it. I've heard other people say similar things but I don't know. Maybe some of you have other opinions.

I've bought probably 6 factory reman Edelbrocks from All American Carb when they have a booth at Turkey Run and all I have ever done was bolt them on and go. I have two 600's on my 27 now with the same results.

But there is nothing wrong with Rochesters, either. Tons of cars and boats came with them and they are pretty simple to go through.

Don

Yeah, I know they are very popular. I was at a show last weekend and saw a bunch of them on different engines, most with no spacer at all. Go figure. Anyway, I've emailed Edelbrock with the whole story and all of my specs so we'll see.

I thought I would give an update on this issue. I sent a Quadrajet I have to All American Carburetor in Florida and had them rebuild/restore it for me. I couldn't believe how this thing looked after I got it back. Simply amazing. Every piece of linkage, every screw, spring, etc. looked like a brand new piece. Anyway, I installed it with a 1/4" base gasket and have had no more problems starting when hot. It doesn't flood anymore nor do I have to wind on it. I doesn't hesitate, or stumble at all. I still don't know why I was having problems with the Edelbrock considering I had been running it on another engine without problems but oh well. Thanks to all for your assistance, opinions, and input.