Hard too start hot sometimes

[Joec123able]

Got 73 k-20 with a 75 Chevy 350. Has an edelbrock carb I don't know much about besides electric choke. Everytime I cold start it, it fires up instantly no problems. Yet when ever i drive it any distance and get it hot and it sits for any period of time I have to crank on it for 4-10 seconds before it will fire up and then when it fires it will run like crap for a second and then clear up and drive fine. I can't figure it out, the choke plate is opening fine when hot. I ahve noticed sometimes the fuel filter will be completely full when I shut it off and other times half full.

[SkinnyG]

Likely heat-soaking the fuel bowl, boiling the fuel, which floods the engine. 

Once the float bowl drops, the fuel pump spring begins pushing the next load of fuel through the fuel lines into the carb.  Where it boils, and floods the engine.

When my truck is hot, I start it with the throttle all the way open to flood clear it.

You could try a heat shield, or a wooden carb spacer.

I notice you have headers - I do too.  This contributes to under-hood temps; not helping us.

This is one of the main reasons why I will be fuel injecting the truck this summer.

[Joec123able]

Thanks for the help. I think I'm going to try starting it with the throttle all the way down next time and see if that helps. I had tryed a couple times starting with the gas half way to the floor and that didn't seem to help. Those headers do get it hot as heck under the hood

[timthescarrd]

Looks like an Edelbrock 1406 (there should be a number on the pass front side of it right below the bolt to the manifold.  I run the same carb on mine.  Heat is likely your issue but how does it run otherwise?  Does it seem to run rich when it is running? 

Typically those carbs only want 5-6 PSI of fuel pressure coming in and a mechanical pump can put off as much as 14 so a pressure regulator helps.  Also make sure you aren't pushing the pedal down before trying to start it hot, that should only be done cold.

The lighter colored metal peice between the Carb and the Intake is a spacer, and hopefully a squarebore to spreadbore adapter, if it's solid aluminum, changing to a phenolic (plastic) one can help against heat-soak too

I also notice that the Vacuum Advance is unplugged on your distributor, Someone may have changed the timing because of that, which could cause hot start issues.

[Stewart G Griffin]

The other thing to try is while you are cranking push the accel pedal halfway to the floor.

[Rattler12]

Take the edelbrock carb off and throw it in the trash. Get a Holley or a quadrajet rebuild from Summitt or Jet.....jm2c'w

[gunrac]

Take the edelbrock carb off and throw it in the trash. Get a Holley or a quadrajet rebuild from Summitt or Jet.....jm2c'w

Hmmm.......

[Dan75k20]

I have no problems with my 1405 600 cfm on my 355 what is yoour timing set at?

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[Joec123able]

It seems to run pretty Rich and actually a couple times acted like it was going to keep running when I shut it off. That's probably a timing problem correct? I have never messed with timing so I'm clueless. Would hooking up the vacuum advance do any good?

[SkinnyG]

Timing ~may~ cause dieseling if the timing is retarded and allowing the combustion chamber to run hot. A lean condition can do the same, or spark plugs in too hot a heat range.  It's a hot combustion chamber that is causing dieseling.

[Irish_Alley]

most have hit the nail on the head imo. it seams like a timing issue, the whole point of a vacuum advance is to advance the timing when under vacuum (or running). so you can have youre base timing set at 15 or so degrees then once the engine is started it will pull vacuum and advance the timing to 26° or so depending on a couple factors. but make sure the advance is working good then set the timing 12-15° on manifold vacuum and see how she acts. if the timing is too far advance it will almost act like a weak battery and be really slow to restart. if yours doesnt do this then ignore everything i just said and just check the timing to see where its at

[Irish_Alley]

just saw this
http://forum.73-87chevytrucks.com/smforum/index.php?topic=32746.msg280325;topicseen#new

[rich weyand]

Check out this post to tune your Edelbrock.  Ignore #7 for now.  Do the rest.
http://forum.73-87chevytrucks.com/smforum/index.php?topic=26985.msg224714#msg224714

Then set the ignition timing.  Read this:
http://forum.73-87chevytrucks.com/smforum/index.php?topic=32085.0;nowap

BTW, manifold vacuum on the Edelbrock is the port with the plug on it, to the driver's side of the PCV port in the center, not the passenger's side port with the piece of hose with the screw in it.

[Joec123able]

Thanks so much to everyone for the help I think I have enough info to figure it out now, only question I just want to make sure that I would plug the vacuum advance into this port on the driver side bottom of the carb correct?

[Irish_Alley]

usually its at the base of the carb but start the motor and put your finger over the port. if theres vacuum then its manifold if no vacuum its ported