hi , my car was running fine in the spring...idle was spot on .i haven't

changed or done anything on the engine....plugs wires gas filter etc..all new,,,anyways, what can make my carb not idle ...it starts fine and choke comes on and come off right away....and if i'm driving it takes it's gas and revs up fine....only at idle it runs rough and the rpm goes from 900 too 500 and wants to shut off...but stays on and goes to 1100 and back down again...besides the idle mix screws which i have to turn out quite a bit to keep the engine running...but it's like they don't work unless they are screwed in all the way..,,what controls the idle ?...do i need to clean the metering rods?...the carb is a 1406 edelbrock with elec choke...2 years old and ran great right out of the box...any help is appreciated,,i know there are edelbrock haters ...but what could of caused this carb to run great a month ago and now idles bad?...thankyou........forgot to mention ,,went from 700r4 to t5...anything to do with this?

 

anyone?

 

it might not be the carb, it could be the ignition or a vacuum leak or the fuel pump

 

Sounds like a vacuum leak to me.

 

thankyou for the response...it runs well at higher rpm's...in 2 nd 3 rd gear it takes it's gas fine ..just at idle or at a red light ,,it will go up and down and struggle to stay on ,,,but if i give gas ,,,engine will stay on..there are 2 vacuum hoses ,,one for the distributor and the other for the pvc valve ,,both look fine ,,anything else i should look for?....thankyou.

 

what vacuum leak ,,how?...thankyou.

 

idle going up and down sounds more like a timing, try retarding the distributor while its doing it, sound like its a lil bit too advanced

 

hi , why would the timming be off...it ran great with this carb last year and the 1st time i started it this spring ,,i didn't touch the timming ...it would still be set correctly if it wasn't touched...what do you think?...thankyou.

 

when u say it ran last year and then u say started this spring, do u mean you changed the carb or u stopped the car???? anyways i would say check your timing, i had this problem and went nuts for weeks checked everything and nothing seemed out of order then i messed with the dist and woala i still cant digest it was the timing causing my problem lo, but again im just saying thats what happened with mine, i cant guarantee you have the same problem but try checkin it you got nothing to loose

 

i ran the whole summer with this carb last year...ran great....no issues...never touched the timming...then stored it for the winter and took it out this spring...it ran great ...but since that 1st time this spring the idle has been all screwed up...i was low on gas and i think maybe something is in the carb....

 

I don't know much about Edelbrock carbs other than their quality is suspect. I've heard stories of these carbs suddenly just running like crap, but I haven't heard many ever state the reasons why.

 

edelbrock has it's share of people bashing these carbs,,,i guess within reason,,,i still think the best carbs are the q-jet ...and some people bash those too....at the track i have constantly heard bad things about holley...the edelbrock design is very simple and yet they have issues like all other carbs,,,go figure...i just need to figure why it's idling bad...

 

i know if the secondaries are open to much at idle it can do this.. on a holley sometimes the idle air screw cork gaskets can dry up and crack/shrivle up. not sure about edel's but maby they have a simular issue? if you have any little plastic caps on any vacume ports, check to see if they are cracked as this can also be a vac leak. check vac hoses for cracks. run the car and choke off the carb with your hand. if it dies you have no vac leak. if it surges you have a vac leak. may aswell chack the timing to it cant hurt

 

i will do that test with the carb cleaner and see if there is a vacuum leak ...if no leak ,,don't know what else to do ...i'll post results...

 

hi , a freind of mine over the phone explained to me that the butterfly for the choke can be open a little and this would cause my rough idle and have the idle screws have no affect....that this needs to be shut ,,,he says to look into the carb and open the choke flap and see if it's slighlty opened...where do i find this adjsutment if it's opened ...what do i adjust to fix this bad idle?...thankyou.

 

Whoa. With the engine cold the choke is SUPPOSED to be slightly open - while the motor's running.

As the engine warms up the choke should gradually open and be completely open after a few minutes of running.

If the choke is closed with the engine warmed up it can cause some issues. Primarily a too rich mixture-but it's unlikely this is your problem.

Verify that the choke is functioning as it should (closed cold/cracked open on start up/completely open when hot) before dickering with any adjustments.

The Edelbrock sticky may help some:

https://www.thirdgen.org/forums/carb...e-rebuild.html

Don't use your hand to choke the carb throat, use a rag. A backfire at the wrong time might otherwise be painful.

 

thankyou ,,good avice,,,but he was saying that it's not the choke flap that needs attention on these carbs..it's the butterfly...underneath the choke flap...he says with engine off/cold obviously to open the choke flap and put my finger in there and if you can feel the butterfly with the tip of your finger not closed all the way ..this is the bad idle issue...and that the idle mix screws with this butterfly even slightly open have no to little effect ,,,i was wondering if it's been heard of and if yes,,,how do i close thid butterfly?..what adjustment to make...my freind was on his cell long distance...so he explained this too fast!!

 

Curb idle adjustment opens the primary throttle blades slightly. They need to be slightly open or the engine won't run. Open too far and, yes, the idle mixture screws won't affect idle mixture much as the motor will be pulling a greater percentage of its fuel from the primary circuits.

If this were the case you'd likely have a very high idle though-unless it were compounded by other problems.

Read through the stickies.

 

You say you stored the car over the winter - what did you do to prepare the car for storage?

 

hi 57...well the usual...jacked the car up and had it on stands,,,un plugged the battery and trickled charged once tn a while...filled up the gas tank and put in a can of fuel stabilizer...i guess that's it...car is in a heated garage...

 

did the hand over the carb test ...it almost died as i had the rag on the carb...then with carb cleaner i sprayed near the gasket at the base of the carb ,,idle seemed to stay still...i then used the carb cleaner and sprayed some inside the carb while running and accelerating ,,,it helped the idle quite a bit....it ran much better after than and actually held it' s idle for 45 minutes until i saw it fluctuate a bit again..

 

Unless you ran the engine after adding the stabilizer, it wouldn't get into the fuel pump and carb. While the stabilizer helps, you can still get evaporation, especially out of the carb, that will leave residue that can clog passages later (doesn't necessarily have to happen when you first start it in the spring).

 

what do you recommend? rebuild?

 

You can try the cleaners, both added to the tank and sprayed in/on the carb. If that doesn't do it, then you'll have to disassemble and clean (which basically means "rebuild").

 

the easiest way to figure out if its the carb or something else is to simply borrow a carb from a friend and see if the problem continuesif it continues it has nothing to do with the carb, the next step to do is to make sure none of the lines are clogged with any unwanted residue, then take off your main fuel line and turn the key if the fuel pump squirts gas out of the fuel line then its still good and the gas lines are good, from there if none of those helped i would be lost as well.

 

that'a a good idea...but unfortunately most of my freinds don't have a spare carb lying around,i guess i will spray the carb a little more with carb cleaner and take the car for a good long ride and see....it is already much better than before with the 1st cleaning and additive cleaner in the tank...

 

i would let you try mine but im sure you live rather far lol

 

yes,,,but actually new jersey from montreal canada isn't really that far!!.
it would have to shipped ...i guess if it doesn't get better ,,i'll rebuild it...

 

if you know how to clean an rebuild it then that would be a good thing to do, i just finished rebuilding my friends carb and his car ran alot better after that.

 

ya, i guess if it doesn't run like it used to ,,,i will rebuild it,,,i'm no expert.i have rebuilt the previous carb on this car ,,it was a holley and it ran much better after that ....then it started to bog the next summer and i questioned my abilities and got it rebuilt by a pro ...it was the same thing , it bogged and stank of gas etc...so i went to an edelbrock ...i bolted it right out of the box and it ran great and no hesitation for at least 2 summers...this summer different story...idle is erratic...but i did stay with little to no gas in the tank...i won't blame the carb for that....if i had the original q-jet this engine came with i probably would still have it today...i'll take it off it it doesn't shape up and rebuild it....these edelbrocks seem way simpler to re-build than holleys...have you rebuilt one?

 

hi there, i just cleaned out the carb more with carb cleaner and filled up the tank and put in another gas tank cleaner..it runs much better...it keeps idle pretty steady now,,not perfect as it was before ,,,but it's getting there..i removed a few plugs ,,i noticed that they are not black at all...they actually are sort of white or basically clean ..it this carb running too lean?...i have the idle mix screws tourned out quite a bit...i thought for sure the way the mix screws are out that it was running too rich instead...