Restarting a warm engine

[Coach]

Looking for some advice from my Chevy friends. Let me start off by saying this is my first truck, so everything is a learning experience. When she is cold, I can pump the gas 2-3 times and she will fire right up. If I drive around for a bit and then park the truck for 30 minutes or longer, it's tricky to get her started. Usually I will turn the key and it sounds like it wants to start but won't unless I give it a little gas, then she will start. Is the right procedure on a warm start to pump the gas 1-2 times then start it? I don't want to flood it, so I have avoided warm starting it that way. The engine is a 350/290hp that runs great and a Holly 670 Street Avenger Carb with a Chevy Performance HEI Distributor and Wires. It could be the cold weather as well (I've only had the truck since late September and then it was in the shop for a few weeks right after that getting the new engine put in). Timing is set to factory recommended specs (10 degree initial with 32 total advance) and the vacuum advance is hooked up as it runs better that way (Chevy recommends leaving it disconnected for some reason). Thanks for any help you can provide.

[michael bustamante]

is there a spacer under your carb?

[cleszkie]

The old starting instructions on the underside of my drivers side sun visor say to depress the accelerator pedal something like halfway and crank engine to start a warm engine. Give give that a shot.

[57larry]

do you have an electric choke on the carb?

[Coach]

No carb spacer on it right now. What does the spacer do exactly? Love the sun visor instructions also, I will give that a try as well. It does have an electric choke.

[Hubscrub]

i usually give little gas when cranking hot engine, unless i just cut it off then right back on. really do it without thinking catch my self doing it in my one fuel injet. truck too. Also if you don't know already if you flood it just floor the accelerator and hold while cranking it will clear it out and start might chug a little when it starts nothing a couple revs won't take care of.

[enaberif]

Heat soak. Should either be or need to put a spacer or insulator under the carb to help prevent this.

[LockDoc]

Originally Posted by enaberif

Heat soak. Should either be or need to put a spacer or insulator under the carb to help prevent this.

Heat soak is normally caused by an overheated starter & solenoid. If you have a heat soak problem the engine will turn over very slowly or not at all when the engine is at operating temperature. The spacer or insulator is used to prevent the fuel from boiling in the carb float bowls, from too much heat. Two different things.

LockDoc

[JeffD72]

Originally Posted by LockDoc

Heat soak is normally caused by an overheated starter & solenoid. If you have a heat soak problem the engine will turn over very slowly or not at all when the engine is at operating temperature. The spacer or insulator is used to prevent the fuel from boiling in the carb float bowls, from too much heat. Two different things.

LockDoc

Not trying to hijack this thread, but heatsoak sounds like the problem I have. What seems to be the most effective fix?

[jjzepplin]

All my old Chevy's never needed any foot throttling to start after warm up. However my 406 does. It has a 2" spacer under the Avenger carb. I think it's because of the added area the fuel has to go to get to the engine. My 307 just cranks right back up no prob. It still has the 2 bbl and I think it has a 1/4" stock spacer down below made of some phenolic sort of stuff.

[joeydurango]

On my old Nova - what I drove as a teenager - I had the exact same problem as the OP. Never did figure out the cause, but it did need a little pedal work to start when hot.

[UMDSmith]

Isn't that called vapor lock, where the fuel is atomizing in the carb bowl and not the cylinders due to the heat that built up.

[1972BlueC20]

I'm going through the same thing with a brand new crate from GM....it's the 350 / 330 HP with Vortec Heads.


Starts fine cold, but after it sits for 20-30 minutes it seems to be flooded and won't start right up without standing on the ignition and or giving some gas....then it smells very rich for a few minutes.

My first course of action is going to be to install a fuel pressure regulator and set to 5.5 PSI....if that doesn't work.....then I'll get a 1" phenolic spacer

I'm hoping one of those things sort the problem out.

[LockDoc]

Originally Posted by UMDSmith

Isn't that called vapor lock, where the fuel is atomizing in the carb bowl and not the cylinders due to the heat that built up.

Vapor lock is on the same order but occurs in the fuel line. Before the fuel gets to the carb.

LockDoc

[no1udknow]

It may be your electric choke is closing and causing your idle mixture to be too rich, by opening the throttle plate, you are introducing more air to the mixture. On the street avenger, there is a idle adjustment screw on each bowl. give each one about 1/4 turn in and see if it is any better. Engines start better cold when they have a rich mixture, which is why we have the choke plate. The choke plate should over come the slight adjustment you make to the idle screws, along with the accelerator pump priming you do when you are pumping the gas. But leaning out the idle mixture a touch might help it start when it's hot. Give it a try, if it doesn't work, you can easily put it back.

[R.L.]

If my engine doesn't fire right up when I hit the key I press the gas pedal all the way to the floor and she fires, most time I don't even let off the key.

[sprint_9]

Try pushing the gas pedal to the floor all the way, just once, release the pedal all the way up and take your foot off of it and try to start. Try it for both cold and warm starts.

[Redline novdog]

I have to put the pedal to the floor to get mine started after sitting for 20/30 minutes. Put a kit in the carb and thought I epoxied all the well plugs on the old 4jet. Evidently something is boiling/leaking the fuel into the intake