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Old 07-18-2014, 10:44 PM   #1
amccomb
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Edelbrock carb hard starting

I have a 66 k10 with a 350, I have Edelbrocks top end kit 2022. I have a 600cfm Edelbrock with a manual choke. I am having problems with starting the truck when its hot. I have done a bunch of research, some guys are having good luck with spacers. So here is my question what spacer do you think will work the best?
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Old 07-18-2014, 11:49 PM   #2
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Re: Edelbrock carb hard starting

Sounds like its running to rich...Instead of a spacer I'd lean it a little...check your spark plugs and see what shape they're in...that'll tell you right away if your running to rich or lean. Your ignition may not be all that good either...you running a good HEI?
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Old 07-19-2014, 12:27 AM   #3
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Re: Edelbrock carb hard starting

Yes, I am running a good HEI just had it tested and timing has been set. The truck starts great when cold just turn the key, I don't have to pump the gas nothing. After any length of driving I turn it off and it starts really hard.
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Old 07-19-2014, 08:23 AM   #4
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Re: Edelbrock carb hard starting

Every Edelbrock I have had does the same thing the hotter the weather the more it is hard to start after stopping. I have heard a insulated spacer fixes the problem.
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Old 07-19-2014, 08:25 AM   #5
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Re: Edelbrock carb hard starting

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Originally Posted by firemanjimtfd View Post
Every Edelbrock I have had does the same thing the hotter the weather the more it is hard to start after stopping. I have heard a insulated spacer fixes the problem.
Yep. The Edelbrocks don't like the heat. Everyone I know down here runs the insulated spacers and the issue is no more.
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Old 07-19-2014, 09:26 AM   #6
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Re: Edelbrock carb hard starting

amccomb. yes it's a problem with these carbs. I learned that I can hot-start by treating it like it is flooded (which it is). when you go to start (hot), don't pump the accelerator just hold it down. I also found, at least on mine, that I only have to hold it 1/2 to 2/3 open (rather than all the way to the floor like you'd normally do with a flooded carb).

that doesn't cure the problem of course, you'll want some type of insulated spacer. there are several types, including ones made from wood which is an excellent insulator. Edelbrock makes this (which I bought 'cause I don't want/need a spacer):
http://www.summitracing.com/search?S...yword=edl-9266

I actually haven't put it on yet since the method described works and I don't drive the truck much. I just haven't gotten around to it
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Old 07-19-2014, 09:55 AM   #7
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Re: Edelbrock carb hard starting

I'm running a 600 edelbrock stock outta the box on my I6 292...has an HEI and headers, but all stock after that. Starts right up hot or cold..course..carb doesn't have a ton of miles either...I let mine sit for..oh...couple hours...and that's when I had a hard time starting...mainly cause I made the mistake of choking it, but putting the pedal to the floor cleared things right up. lol Maybe I'll look into one of those spacers.
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Old 07-19-2014, 10:49 AM   #8
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Re: Edelbrock carb hard starting

I use the Edelbrock insulated base gasket which I bought at the parts store. Works great.
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Old 07-19-2014, 01:50 PM   #9
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Re: Edelbrock carb hard starting

I used the 1/2" Edelbrock 8723, works like a charm:



http://www.summitracing.com/parts/edl-8723
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Old 07-19-2014, 04:13 PM   #10
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Re: Edelbrock carb hard starting

Also note that the Carter (A.K.A. "Edelbrock") AVS/AFB carbs like that are known for not tolerating the higher fuel pressures a lot of pumps put out; a lot of people think anything over 5.5PSI is enough to cause problems. 4-5.5PSI seems to be the normal recommendation.

Also, (at least sometimes) the crap mechanical pumps can build really stupid pressure; my father said his pegged a 20PSI gauge at times!

My father had hot start problems with his, and AFAIK he doesn't anymore with the pressure regulated down (something like 4.5PSI IIRC).

Might not be the problem, but it's something to consider.
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Old 07-19-2014, 04:42 PM   #11
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Re: Edelbrock carb hard starting

Thanks for all the advice guys I will run up to the parts store and get me one of those spacers. I have a regular mechanical fuel pump, and I still have the tank in the stock location behind the seat. Are the mechanical fuel pumps prone to putting out too much fuel pressure? I also have a wix fuel filter in line under the cab. Thanks for giving me the exact part number makes it idiot proof. haha
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Old 07-19-2014, 04:58 PM   #12
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Re: Edelbrock carb hard starting

Quote:
Originally Posted by amccomb View Post
Thanks for all the advice guys I will run up to the parts store and get me one of those spacers. I have a regular mechanical fuel pump, and I still have the tank in the stock location behind the seat. Are the mechanical fuel pumps prone to putting out too much fuel pressure? I also have a wix fuel filter in line under the cab. Thanks for giving me the exact part number makes it idiot proof. haha
The big-pressure pump described was a generic "Airtex" brand stamped-together mechanical pump. I've heard of other guys having similar problems with the new pumps like that; I personally like the ones that screw together (I ran a real 50's AC-Delco pump I rebuilt on my 283).

I also think (IIRC) that the later SBC pumps (some of them, anyway) are spec'd at 6-8PSI to begin with, which everyone seems to agree is too much for the Carter carbs to deal with.

Never hurts to test the pressure and see what it is. If you search "sbc mechanical fuel pump pressure" you get a lot of results from pumps putting out too much pressure.
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Old 07-19-2014, 06:07 PM   #13
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Re: Edelbrock carb hard starting

what's probably happening is heat soak. the gas in the bowls of the carb evap as the motor gets hot. this is what happened to me, wouldn't start when hot and hard to idle. I installed a 1" phenolic spacer under my edelbrock and it's gone. you can try a new fuel pump but doubt if that's it. just me 2 cents.
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Old 07-19-2014, 06:19 PM   #14
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Re: Edelbrock carb hard starting

which style of spacer is better or is there a difference between the plastic and wood laminate? Is the open design better or the 4 hole?
4-Barrell Carburetor Spacer #8719 by Edelbrock I am considering this one.

Last edited by amccomb; 07-19-2014 at 06:38 PM.
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Old 07-19-2014, 06:21 PM   #15
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Re: Edelbrock carb hard starting

Quote:
Originally Posted by davbowen View Post
what's probably happening is heat soak. the gas in the bowls of the carb evap as the motor gets hot. this is what happened to me, wouldn't start when hot and hard to idle. I installed a 1" phenolic spacer under my edelbrock and it's gone. you can try a new fuel pump but doubt if that's it. just me 2 cents.
I just gave another potential thing for him to check out, since no one else mentioned it. The Carter type carbs are known to not tolerate as much pressure as a lot of pumps produce.
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Old 07-19-2014, 09:30 PM   #16
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Re: Edelbrock carb hard starting

Quote:
Originally Posted by amccomb View Post
which style of spacer is better or is there a difference between the plastic and wood laminate? Is the open design better or the 4 hole?
4-Barrell Carburetor Spacer #8719 by Edelbrock I am considering this one.
what, you don't like my suggestion?

Which of the 2 you mention (wood or plastic) is better? I think wood is the better insulator but frankly don't think it matters because they both will do the job just fine. (so will the heat insulator gasket )

as far as holes vrs open, I don't know which type of manifold comes with the "top end kit" (hopefully it's a dual plane if your truck is a DD) Assuming it's a dual plane, I think it depends on the type of driving you'll be doing. some manifolds have a fully divided plenum some have a notch, the notch tends to move the power band up slightly. the open spacer accomplishes much the same effect. I think the 4 hole or the divided type is preferable to the open for near stock DDs, but lots of guys run the open.
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Old 07-19-2014, 09:46 PM   #17
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Re: Edelbrock carb hard starting

Haha your suggestion is perfect, I just figured if a .3 heat insulator works the .5 will just be a little bit better. Thanks for all your help guys! 1/2" Edelbrock 8723 has been ordered we shall see if that fixes her, I will check the fuel pressure when I install the heat insulator.

Last edited by amccomb; 07-19-2014 at 10:04 PM.
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Old 07-20-2014, 02:06 PM   #18
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Smile Re: Edelbrock carb hard starting

If what u ordered does not cure the problem and heat continues to seem where the problem lies, you may wanna buy one of the below heat "shields"--it took one of them to cure an AFB boilover-when-hot condition on a customer's 327, stock 250 hp exc. for carb and intake.

Good luck with your project!
Sam

http://www.summitracing.com/parts/hly-108-70/overview/
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Old 07-20-2014, 08:35 PM   #19
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Re: Edelbrock carb hard starting

Quote:
Originally Posted by davbowen View Post
you can try a new fuel pump but doubt if that's it. just me 2 cents.
Confirmed with my father today that all his hot starting issues went away when the fuel pressure was corrected.

Side note: I also bought another car today with a "new" fuel pump that chugs black smoke. Wouldn't be surprised at all if I stick my good pump on there tomorrow and it runs like new.

Not to say that's always the problem, but I'm telling you; watch out for these POS fuel pumps...
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Old 07-20-2014, 09:27 PM   #20
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Re: Edelbrock carb hard starting

yes, pumps do get old and it wouldn't hurt to install a new one. but edelbrocks are known to suffer from heat soak on hot motors. a spacer will fix that, fixed mine anyway. I believe the gas pressure should be right about 6 psi max. the wood 4hole square bore spacer you got is a good one and will insulated better than plastic at that thickness. you just need to keep the oil/gas/water away from it, it's compressed wood.

let us know how it all works out.
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Old 07-20-2014, 10:18 PM   #21
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Re: Edelbrock carb hard starting

Quote:
Originally Posted by davbowen View Post
yes, pumps do get old and it wouldn't hurt to install a new one. but edelbrocks are known to suffer from heat soak on hot motors. a spacer will fix that, fixed mine anyway. I believe the gas pressure should be right about 6 psi max. the wood 4hole square bore spacer you got is a good one and will insulated better than plastic at that thickness. you just need to keep the oil/gas/water away from it, it's compressed wood.

let us know how it all works out.
No, it has nothing to do with pumps "getting old"; it's brand new pumps that cause problems. It seems to be common now, which is probably why so many insist that these trucks get really poor fuel economy and that carburetors don't work.

Most recommend 5.5PSI or less for the Carter style carbs. At the least I'd put a gauge on it and check it, and add a regulator if the fuel pump is making over 5.5PSI. Even if it's just making 6-8PSI like many are supposed to, that's really too much. IIRC my father has his @ 4.5PSI.

That said, I'm not saying heat soak may not be the issue for the OP.
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Old 07-20-2014, 11:00 PM   #22
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Re: Edelbrock carb hard starting

For what it’s worth, I’ve run Carter AFB’s or Edelbrock AFB’s with a mechanical pump most of my adult life. I loved mechanical pumps because they lasted for decades and I never had one fail. My experience was electric pumps was terrible, left stranded several times, so I had little use for them. That all changed within the last few years.

A couple of years ago I had so trouble much starting my engine I added an electric pump just to prime the system, turned if off and let the mechanical pump take over. As a safety precaution I replaced my perfectly functioning mechanical fuel pump with 4 new ones, the first one was the type that could clock the position (if was defective and the pump lever pieces fell out of the housing). It was replaced with 3 more sealed models (different brands from different stores), and every one of them put out over 10 psi, completely flooding the carb.

I installed a standard Holley 12-803 regulator set at 4.5 psi. which helped with the flooding, but I soon developed a surging problem where the engine would flat run out of gas for no apparent reason. A quick jolt on the booster switch brought the engine back to life before we had a chance to coast to the side of the road.

The bottom line, I have absolutely no confidence in mechanical pumps any longer. I got rid of it and rewired the electric pump to provide constant fuel. Figuring my previous failures were probably my fault, this time I powered the pump through a relay and dedicated ground, mounted the pump at the bottom of the front of the tank, ran a racing pre-filter between the tank and the pump, and left the factory GMC canister filter under the passenger seat.

Once I figured out what the new engine wanted to start, I’ve never had any issues at all. I set all the controls where they want to be, hit the key and it fires up. I don’t know what is different between mechanical fuel pumps from 40 years ago, but I done with them unless something else changing.

Just a heads up for anyone considering the purchase of a new mechanical fuel pump. Ask yourself which technology all of the new cars have.
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Old 07-20-2014, 11:53 PM   #23
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Re: Edelbrock carb hard starting

THANK YOU!

FWIW, I rebuilt a real-deal 50's-60's AC-Delco pump when I had the 283 in my C30; works/worked great. Bought a NOS pump for another with a six. In the future I'll be running real rebuilt/NOS pumps like that or electric. BTW, it cost about $40 for the kit; well worth it IMO.

I bought the kit from these guys: http://www.maritimedragracing.com/an...rts_cellar.htm
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Old 07-21-2014, 03:15 AM   #24
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Re: Edelbrock carb hard starting

The Edelbrock mechanical pumps are setup to run the 5lbs pressure that their carbs need.
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Old 07-15-2017, 04:09 PM   #25
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Re: Edelbrock carb hard starting

This is an interesting thread and points to some of my issues with my Edlebrock 1405. I struggled with a rebuilt 1405 until I gave up and bought a new one and still I have issues.

The first issue I had seemed to be rust. I pulled the original fuel tank and I couldn't see a bit of rust. I reinstalled and it seemed that the mechanical fuel pump was toast. I replaced it with a new one I happened to have and the truck ran great! .....right up until it died on me! It started to die as I was driving. We pushed it into the parking lot and removed the air cleaner only to hear the the sound like a kettle on boil. I pulled the carb and thought that I would buy a spacer but not sure if I don't have a combination of issues?

I have a 350 SB out of a 1971 El Camino. It is stock with a OEM HEI Distributor. I have an older Edelbrock Performer Intake which I believe is a 2101 4-bbl Spread-Bore Carb Flange (non-EGR). On top of that is an Edelbrock 2696 Four-Hole Square-Bore to Spread-Bore Carburetor Adapter and then my Manual choke with 4-barrel square-bore carburetor flange 1405.

Question is can I, or should I, run a spacer to insulate from the heat if this is a "fuel Boil" issue? If so, and I did buy a Edelbrock 9266 Heat Insulator Gasket, where do I place it? Between the Adapter and the carb? Lastly, could this all be a fuel pump issue due to the mechanical fuel pump? Shoud l I run an electric low-pressure pump?

Thank you to anyone who tackles this. It's killing me not to drive this truck!

Dan

Last edited by Shtudwn; 07-16-2017 at 04:55 PM.
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