1977 Rough Idle Stalling Elderbrock Carb..

[Twreck]

I have a 1977 c10 with a 350 5.7 and an elderbrock carb.

I have been having some trouble with the truck idling. it sounds rough and vibrates the car a bit, also likes to try to stall under light throttle. It has an elderbock carb and i've played around with the two A/F screws but they dont seem to do much of anything except stall the engine once turned in far enough. I have read that you can try spraying carb cleaner in the fuel bowl vents, however I thought I would try to get some opinions before just letting er rip with the gumout.

 

[350runner]

Seafoam "deep creep" works wonders... Has this problem started recently or has it been on going for a while? Has the engine had a tune up?

Sent from the dust in front of you!

 

[firebane]

I have a 1977 c10 with a 350 5.7 and an elderbrock carb.

I have been having some trouble with the truck idling. it sounds rough and vibrates the car a bit, also likes to try to stall under light throttle. It has an elderbock carb and i've played around with the two A/F screws but they dont seem to do much of anything except stall the engine once turned in far enough. I have read that you can try spraying carb cleaner in the fuel bowl vents, however I thought I would try to get some opinions before just letting er rip with the gumout.

Those screws are your idle mixture screws. It dies when you turn them all the way in because its leaned out so much it can't run.

 

[MadOgre]

I have a 1977 c10 with a 350 5.7 and an elderbrock carb.

I have been having some trouble with the truck idling. it sounds rough and vibrates the car a bit, also likes to try to stall under light throttle. It has an elderbock carb and i've played around with the two A/F screws but they dont seem to do much of anything except stall the engine once turned in far enough. I have read that you can try spraying carb cleaner in the fuel bowl vents, however I thought I would try to get some opinions before just letting er rip with the gumout.

Sounds like a vacuum leak. make sure all intake bolts are snug and the carb is snug to the intake and that all vacuum hoses are in good shape and connected properly. And that there are no ports that unconnected or capped off.

Turn those 2 screws about 2 1/2 turns out from bottom

 

[jetman]

As mentioned by MadOgre, it does sound like a vacuum leak. If you have some acetylene or propane gas, let gas flow around the possible leaky places, if truck engine "perks up" you have found the vacuum leak.
Failing that, the Edlebrock carb is pretty easy to open up and clean out. Simply unbolt the carb from engine, remove 8 or 9 Phillips screws from top of carb and remove upper section of carb. Get some carb spray and clean out inside of carb as discussed. (unlike the Holley's-QJets of old, I have not been able to find the fuel bowl vents on the Edlebrock)

 

[MadOgre]

As mentioned by MadOgre, it does sound like a vacuum leak. If you have some acetylene or propane gas, let gas flow around the possible leaky places, if truck engine "perks up" you have found the vacuum leak.
Failing that, the Edlebrock carb is pretty easy to open up and clean out. Simply unbolt the carb from engine, remove 8 or 9 Phillips screws from top of carb and remove upper section of carb. Get some carb spray and clean out inside of carb as discussed. (unlike the Holley's-QJets of old, I have not been able to find the fuel bowl vents on the Edlebrock)

Yes but do it on a clean work bench so you don't loose anything

 

[firebane]

Yes but do it on a clean work bench so you don't loose anything

I find large cookie sheets work awesome for carb repairs lol. I have 2 now from when the woman burnt crap permanently to them.

 

[MadOgre]

I find large cookie sheets work awesome for carb repairs lol. I have 2 now from when the woman burnt crap permanently to them.

Good idea

 

[Twreck]

I tried cleaning the carb this morning with is still on the engine, also replaced the pcv valve and grommet and hose as well as spark plugs and air filter and vacuum line leading out of the carb to a round disc shaped object.. Still have a rough idle that gets worse when put in gear.

MafoOgre - there is a port on the right side that looks intentionaly plugged however it has been like that for awhile and this issue started recently after driving the truck more frequently and on longer trips.

Haven't had it tuned up but have tried sea-foam in the gas before with good results but no luck this time and after everything i did today failed to make a difference I dropped it off at the local mechanic.. kinda frustrating cause the idea of having this truck was to learn to fix the problems.. but we shall see

 

[MannyDantyla]

CHECK THE TIMING, I'm surprised no one has mentioned this yet. My engine wanted to stall when starting from a stop. Then I adjusted the timing and it runs perfect now. It was not advanced at all, almost at TDC, now it's avanced 10 degrees IIRC.

get a vacuum gauge, that'll help a lot. I found a used one on ebay for $20.

 

[bucket]

Eh, sounds like my not-so-old Edelbrock carb. That thing just refuses to hold a tune and is only happy about 3 or 4 days out of the month. Give me a Holley or a Quadrajet any day.

Sorry that was not really any help at all, just seemed like a good time to gripe about it, lol.

 

[rich weyand]

A periodic maintenance item on the Edelbrock is to pull the mixture rods and step-up pistons and clean off the pistons and the cylinders they live in. They get dirty, then they stick in the up position. Use a q-tip with solvent or gasoline to clean the cylinders.