Edelbrock carburetor sometimes won't idle (and I'm getting ready to pull my hair out)

[Jimal]

This should be all the pertinent information.

- 65 K10
- 400 SBC of unknown origin
- Completely new (this year) fuel system, from tank to carburetor
- Edelbrock 1406 with electric choke
- HEI is set to 8 degrees initial (if my timing tab is correct)

The truck starts and runs fine on high idle with the choke closed, but some times (most of the time) when I kick it off high idle the truck won't idle. It will run if I keep my foot on the gas, but as soon as I take my foot off, it dies. Give it a little gas and it starts right up, but I have to keep pushing on the pedal to keep it running. Other times - like earlier today - it will run like a champ for a while, then while driving down the road I'll feel a little *cough*, then I start getting part throttle hesitation/stumble, some snapping out of the exhaust on decal, and if I don't goose the throttle the engine dies.

I've checked for vacuum leaks, but I'm not finding any. The gas is fresh (and I added some Sta-Bil when I filled it up last time). It feels like its starving for fuel, but it will run if I keep moving the gas pedal (which I assume means I'm giving it fuel to keep it running).

The truck is otherwise reliable at this point, but this is driving me nuts.

[geezer#99]

It might not be starving for fuel, it could be flooding instead. Moving the pedal to keep it running just lets the extra fuel go on to be burned.
Eddy carbs don't like more than 5 psi.
You likely need a regulator.
Also bump your timing up to 12.

[Jimal]

Originally Posted by geezer#99

It might not be starving for fuel, it could be flooding instead. Moving the pedal to keep it running just lets the extra fuel go on to be burned.
Eddy carbs don't like more than 5 psi.
You likely need a regulator.
Also bump your timing up to 12.

Even with a stock pump? I didn't think of that.

I'm assuming it is 8 based on what I left my adjustable timing light at the last time I tinkered with the truck. It has a cheap aftermarket timing cover and tab, so I'm not 100% sure how accurate that is. The truck cranks and starts like the timing is close if not dead on.

[GASoline71]

More timing... and ditto on the regulator.

Even a stock Chevy fuel pump can put out somewhere around 7 psi. Seen some that were closer to 8 psi.

Gary

[geezer#99]

You might need to prove your timing tab/balancer are correct too.
http://www.crankshaftcoalition.com/w...op_dead_center

[crazy longhorn]

Pull the top off the carb, & check float levels....I had one that was a rich flood @ idle ? I do agree with the rest on fuel pressure(5 psi), & timing. Set at 12-14 initial....not to exceed 34 @ 3000 rpms total on a stock ride(vac unhooked, & plugged)... Longhorn

[Jimal]

Originally Posted by crazy longhorn

Pull the top off the carb, & check float levels....I had one that was a rich flood @ idle ? I do agree with the rest on fuel pressure(5 psi), & timing. Set at 12-14 initial....not to exceed 34 @ 3000 rpms total on a stock ride(vac unhooked, & plugged)... Longhorn

I'm going to try the regulator before tearing into a brand new carburetor. Once I get that figured out and can get the truck to idle properly I'll tinker further with the timing.

[68gmsee]

Originally Posted by Jimal

I'm going to try the regulator before tearing into a brand new carburetor. Once I get that figured out and can get the truck to idle properly I'll tinker further with the timing.

That is the proper move. When we give hints we assume that the person will do the easiest first.

On similar problems I usually check:
1. Fuel pressure
2. Float level
3. Fuel flow (1 pint in 30 seconds or less into plastic container)
4. With breather off manually check for fuel squirting into carb
5. Double check timing and make sure TDC or zero lines up with harmonic balancer mark

[Jimal]

Originally Posted by 68gmsee

That is the proper move. When we give hints we assume that the person will do the easiest first.

On similar problems I usually check:
1. Fuel pressure
2. Float level
3. Fuel flow (1 pint in 30 seconds or less into plastic container)
4. With breather off manually check for fuel squirting into carb
5. Double check timing and make sure TDC or zero lines up with harmonic balancer mark

I ordered up a Holley low pressure regulator. I momentarily considered the Mr. Gasket regulator with the dial on it, but then I remembered what happened with the last Mr. Gasket parts I used, read some reviews that reinforced my opinion on Mr. Gasket parts, and went with the Holley.

[Jimal]

Okay, the Holley regulator arrived. I think I've found a location to mount it, assuming that its orientation isn't important (and I can't find anything in the instructions or online to indicate that it is.) If I turn it 90 degrees counterclockwise from what I have pictured, I can add a bend and a flare to the existing hard line and end up with a better routing for the line up to the carburetor.

[68gmsee]

I'm not familiar with the regulator orientation requirements either but if it's more convenient I'd go for it.

[dirtyjim]

that's just about the same spot I have my regulator mounted in, my stock replacement pump was putting out close to 10# at idle.

[Jimal]

I ended up mounting the regulator on the inner fender and running some rubber line from the pump to it, and onto the filter and carburetor (which i know is not ideal, but I think it'll be fine, at least for now).

https://www.youtube.com/watch?v=h-ok2iCg0tQ

Once the truck warmed up it seemed to run better than it was before. It now responds to either idle mixture screw - which it didn't before - and I can stand behind it without my eyes watering. It became wet and raw so I put the truck away for the day. Tomorrow I'll revisit the engine timing. I also would like to find a snorkel air cleaner with a pre heater setup to get the carb some warm air before it gets up to temperature.

[Jimal]

Originally Posted by 68gmsee

That is the proper move. When we give hints we assume that the person will do the easiest first.

On similar problems I usually check:
1. Fuel pressure
2. Float level
3. Fuel flow (1 pint in 30 seconds or less into plastic container)
4. With breather off manually check for fuel squirting into carb
5. Double check timing and make sure TDC or zero lines up with harmonic balancer mark

1-4. The regulator seems to have solved the problems.
5. After finally getting a good look at my timing tab, I reset the initial timing to 12 degrees. Since it has never idled or run better I'm going to take a leap and assume that the mark on the balancer is accurate. It is finally responding to the idle mixture screws.

[68gmsee]

Great! And thanks for posting the fix. This helps someone else that may have a similar problem.

[5567Cruiser]

Originally Posted by Jimal

1-4. The regulator seems to have solved the problems.
5. After finally getting a good look at my timing tab, I reset the initial timing to 12 degrees. Since it has never idled or run better I'm going to take a leap and assume that the mark on the balancer is accurate. It is finally responding to the idle mixture screws.

I had the same problem with the 1406 and after messing around checking everything I ended up going to a hotter AC spark plug R45T and that corrected my problem.Just a thought in case you have a underload miss.

[Jimal]

Originally Posted by 5567Cruiser

I had the same problem with the 1406 and after messing around checking everything I ended up going to a hotter AC spark plug R45T and that corrected my problem.Just a thought in case you have a underload miss.

I can't remember what I went from and to, but I went with a hotter plug early on in this process. I took the truck for a ride this afternoon and it has never run better. The idle is smooth and there is no stumble at part throttle or hesitation when I step on it. Best of all, it no longer dies when I come to a stop.

I almost don't want this thing to blow up now. Thanks guys; you really talked me off the ledge with this one.

[Jimal]

After going through all this trouble and having the truck run great for a while, I went to a Cars & Coffee this morning, and as soon as I pulled into the place the truck refused to idle. On the way home we stopped to tinker with the carburetor, and after starting the engine repeatedly, having it die repeatedly, and goosing the throttle to keep it running, it popped, and then started running fine.

I got home and decided to break into the new carburetor. Turns out that despite using Stabil, the gas in the carburetor bowl was gelled up. Cleaned the carb out, blew out all the ports, put some Sea Foam in the tank (and a little in the carburetor before reassembling it) and now it is running like a champ again.

Damn crappy gasoline.

[snj8198]

how frustrating

[Joe Pass]

One thing to remember with Edelbrock's is that their idle circuits plug easily and you get these very symptom's you described. It can be solved quickly if you pull the idle mixture screws out and blow compressed air in the openings and re install the mixture screws 1-1/2 turns out. 9 times out of ten this will cure your issue and then you can decide to go further cleaning the carb out or running it. It never hurts to make sure all the above suggestions are checked also...I had these same symptoms several times when I use cheap unbranded gas.
Good luck
Joe

[Jimal]

Originally Posted by Joe Pass

One thing to remember with Edelbrock's is that their idle circuits plug easily and you get these very symptom's you described. It can be solved quickly if you pull the idle mixture screws out and blow compressed air in the openings and re install the mixture screws 1-1/2 turns out. 9 times out of ten this will cure your issue and then you can decide to go further cleaning the carb out or running it. It never hurts to make sure all the above suggestions are checked also...I had these same symptoms several times when I use cheap unbranded gas.
Good luck
Joe

It got a bit more involved, as the bottom of the bowl was filled with gel. This is a picture of the old Edelbrock that was originally on the truck, but this is pretty much what the inside of the new carb looks like.

[richards72chevy]

How old was the new carb and how often did you drive your truck?

[Jimal]

Originally Posted by richards72chevy

How old was the new carb and how often did you drive your truck?

The new carburetor was purchased and installed in August along with new fuel lines, a new pump and filter (the new tank was installed in the spring). I drive the truck mainly on weekends when time permits, but it can sit for a few weeks.

[68gmsee]

That's some nasty looking stuff in that carb! I've never had gasoline gel up in my vehicles but I did find a similar substance in the carburetor fuel bowl in my pressure washer. I hadn't used in about 6 months.

Assuming that using a product like Stabil or similar does not take care of this gel, I would yank the tank out and thoroughly clean that crap out.

On another note. I remember in the old days before "gasahol" working for a farmer driving a tractor. Sometimes these tractors would stay in the barn for almost 6 months and longer and they always started right up every spring.

[Jimal]

Originally Posted by 68gmsee

That's some nasty looking stuff in that carb! I've never had gasoline gel up in my vehicles but I did find a similar substance in the carburetor fuel bowl in my pressure washer. I hadn't used in about 6 months.

Assuming that using a product like Stabil or similar does not take care of this gel, I would yank the tank out and thoroughly clean that crap out.

On another note. I remember in the old days before "gasahol" working for a farmer driving a tractor. Sometimes these tractors would stay in the barn for almost 6 months and longer and they always started right up every spring.

Therein lies the challenge. I need to run the tank down to empty before pulling it out, so that is going to take a while. Meanwhile, whatever is in the tank is getting past the pickup screen and the filter before getting into the carburetor bowl and gumming up the works.