The carb may need bigger accelerator jets or even a bigger pump. Changing the rate the power valve opens also helps.
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The carb may need bigger accelerator jets or even a bigger pump. Changing the rate the power valve opens also helps.
well heres an update....i got a new intake a dual plane airgap and a 600 cfm edelbrock....i put it in and it worked good i drove it for about half a day with no prob...i went to take it out that night and if ran like crap it'd idel extremely low then as soon as u touched the gas it'd jump up in a big hurry then idle would change back and fourth....sooooo i thaught maybe the intake gaskets cause every one said it sounded like a vaccum leak so i changed the intake gaskets and was extreamly carefull putting the new ones on... and it didnt much more and was pretty much the same. and i checked with brake clean for leaks.....then i was driving the other day and as far as i know the fuel pump went(mechanical)....so i changed it with another one i had. i tested it and it ran 6-7 psi.....still ran like crap...so i changed hte fuel filter and ran a clear on near the car to see whats going on....when it runs the filter seems to only have a little fuel in it but it stays constant...sometimes its completely full and sometimes very low and sometimes it getts fuller as it sits for a while...when its running u see the odd air bubbles come up in the filter so i tightened all my connections....i'm running outta ideas here i might try an electric fuel to see if it makes a difference......when i get on it its not to bad until the secondarys kick in then it like falls on its face and makes alot of burping noise...i took of the pcv valve it made it runn a little better...any ideas to help me i'm loosing my mind here.....:confused:
I didnt read much of this thread but I do remember one engine I had that had a big cam and it ran like crap too and there seemed to be no cure. It rocked and burped at idle and when I took it for a full on speed run it would just fall flat when I really throttled it at higher speeds. If I was easier on the throttle it was alright....thought this to be a vacuum problem or distributor but it wasn't. I swapped out the old heads for some new aftermarket World Products Sportsman IIs and it made a world of difference. The thing purred...as much as a huge cam can purr at idle and ran like a top afterwards. You might just need some more flow in the heads. Keep in mind I didnt read the thread and I don't know what heads you have on it. Port whatever you have or put some better flowing ones on...thats if you don't have them already. Other than that I think everyone else probably answered some questions.
sorry the carb isnt the prob i have a 305 duration cam in the 350 and it idles great with stock heads may need to check for vacuum leaks and invest in an adjustable vacuum advance... and get some bigger jets and if it is a vacuum sec get some lighter springs for the secondarys and set your vacuum advance up with lighter springs so the timing will kick in sooner... the prob with the lumpy cam is that its a low vacuum cam so you have to adjust all the vacuum settings
also dont hook the advance up to your port on your carb hook it directly into your intake for full advance
that should help
you might have to drill some holes in your butterflys to equal out the fuel air mixture .... btw if the prob persist you should check for vacuum leaks around the bottom of the carb intake and the line that runs down to your tranny
Sounds ot be lean....... so, richen the jets by 6 sizes and then test it.
i got it to run pretty well but the air mixture screw are out alot
pull the cam out if there is not a notch on the back of the cam berings it my not be getting enoughj fuel /air to the motor or oil for that matter
i dont know if i'm going through the bs of pulling out the cam..i put my 600 cfm edelbrock instead of my dads AFB Carter comp carb it works alot better and the secondary's kick in beautifully as well i changed the hei and it worked better as well. i set the timming at 34 degrees @ 3000 rpm it seemed to work the best there what should it usually run at idle drgrees wise???.....so far it works really well...i had to put an electric fuel pump on the mechanical one didnt seem to keep up...the electric one works well but i keep getting alot of air in the fuel filters and u can see little bubbles comming up one or 2 at a time(i also did with the mechanical one).....i think i must be sucking air from somewhere mayeb the tank pick up maybe??? has anyone had this problem before....sometimes the filter is right full of fuel and another time it looks pretty much empty...any ideas
Hey I noticed in one of your previous posts that you mentioned you were running 6-7 psi. I know from experience that edelbrocks cant handle much more than 5 psi. The manual even says that between 5 to 5.5 is the best. My pump was running 7-8 and it ran like crap--would always stall if i applied the brakes. After putting on a pressure regulator it solved this problem.
i've got everyting together and have been running it for a while. the carb still has a bit of a flat spot a low idle taking off. the idle sounds off unless i put a bit of load on it by letting out the clutch a little. and when i cruise at low idle its like car kinda feels like its jerkingback and fourth...the flat spot is't as bad once its good and warm..any ideas???? i got about 5psi for fuel pressure
Hey Jay;Quote:
Originally posted by jayman54
...I put a bit of load on it by letting out the clutch a little. and when i cruise at low idle its like car kinda feels like its jerkingback and fourth...the flat spot is't as bad once its good and warm..any ideas????
It sounds like your idle circuit is a little lean. You seem to be having a lean misfire at low rpm's.
The jerking around that you are experiencing,.... it is the cam. Try crusing at a little higher rpm's, which might mean choosing a lower gear.
If the flat spot isn't as noticable after it warms up, it only confirms the fact that you are lean.
i'm running a 600cfm edelbrock is there anyway i can change that the idle circuit??
The Edelbrock carbs are very tunable. I bought a tuning kit recently for a customer and had fun playing with all the different options. The kit comes with full instructions as to how to richen the primary and the secondary circuits. Have fun.