six pak problem

[70gtx]

my pressure is starting tom get high ,so im going to have a beer .
i put new ngk racing plugs in,and it still run rough .i put 2 size smaller jets in and a new 3.5 power valve (had 4.5) . it still runs rough at all rpms except idle, smokes out exhaust and burns your eyes.
if i turn fuel pump off while holding it at 2000,3000,4000 rpms it starts running smooth just before it runs out of gas.
only the center is hooked up and i can pull plugs on the side of all three with no gas coming out at idle.

could it be bad set of plugs or that***^^%% center carb? if i send it to holley do they have a way to test it or are they going to just rebuild it.
this is the worst it was run ever.

[6pakman]

ah yes, the old i got the cars runnin rich six pack blues. i know the feelin well. look for these things, fuel level in all carbs. should be just below sight plug. fuel pressure, 6 lbs[no more than that!!!] with car runnin at idle, look down center of carb to see if a fuel is dripping out of squirters if it is, check pwr valve. if not inspect valve body. its a fuel problem no more than that. last but not least make sure that the end carbs ARE NOT dumping gas in the manafold. there are adjustments at the front of those carbs that should NOT BE TURNED MORE THAN 3/4 OUT. if they are they will dump mucho gas down the carb. a/f mixture should be 2 1/2 turns to start then leave them alone. that will get you in the ballpark. and one more thing, try not to let the car run to long untill you find the problem. extra gas can slip by the piston rings , get in your oil, dilute it, and start to hurt the lower end[ie main and rod bearings]. good luck!!

[70gtx]

none of the carbs are dripping at idle.all fuel levels are below the threads,i even left the plugs out while running.not sure on pressure but i inially set at 41/2.
it seems to idle pretty good.but its like it is getting way to much fuel when above idle.a/f set at 3/4 on rear and front ,about 2 turns on center. vacuum is running 6-7 at idle.
its running like the first set of champions that i fouled,miss fired and ran crappy,i had 6.5 power valve and float problems then .
guess ill try a hotter set of plugs ,try that and maybe put the 4.5 power valve back in just incase new power valve isnt seating right or some thing. just dont know where else to go from there. maybe i got bad set of plugs.

[6pakman]

no such thing as a set of bad plugs. they have been around to long to be made bad. you can try a set of hotter plugs but i doubt that will cure the problem. that gas is getting there from one place only and thats the carbs.try this, run the engine for a couple of minutes then shut down. pull the front carb first and look down the throttle bores in the manafold. if you see alot of wetness down there thats your problem in that carb area. check all three manafold areas. it should not be wet. a little shiney but not wet wet. its there you will find it.

[JariV]

I have same kinda vacuum level with my sixpack. All my carbs are new and I have a 300/300/0.572" mech. cam. The problem was that even with 3.5 power valve it dumps fuel. So I got 2.5. It's a lot smoother. And then there's this valve plug. Disables the power valve.

Hope this helps.

-Jari-

[PRO]

I wouldnt assume your prob is the carbs,although it might be,check your spark,it should jump a 3/4" gap,is there any side to side slop in the dist shaft? if so is the reluctor touching the pick up?if points then your prob only firing on 6 cyl.With it running pull off 1 plug wire at a time at the cap,the rpms should drop,if it doesnt that cyl isnt firing.A typical 6pk prob is that most people dont realize that it IDLES off all 6 BARRELS,and you have idle mixture screws in the base plate of the end carbs,usually they have metal plugs covering them from the factory,remove the plugs and adjust the end carbs at idle,the forward carb is accessible but youll have to remove the rear carb to get to its idle mixture screws,set them to the same setting as you did the front.most likely your too lean on 1 or both of the end carbs.If your 6 pk set around for awhile you may have to replace the center carb metering block as it gets clogged up with crap from sitting with fuel in it for long periods of time,its still available from holley,hope this helps...........PRO.......

[70gtx]

im going to mess with the spark a little and see what happens . im in a better mood now . thanks for the help

[70 cudas]

i'v run into these problems before.1 was the fact that they were original carbs and that the body of he carb where the metering block fits against was warped from excessive heat over the yearsand if i remember it correctly an old holley book i had even stated it.the other was that if you used other than holley gaskets the gaskets would shrink a little causing air/fuel leaks and rouuugh idles and a rich condition throughout the rpm range.you can also test the end carbs by blocking the air bleeds in the venturi with your finger tip, and if the eng.idle sped up or slowed down would tell you if its rich or lean.if you have an original holley manual it states this in it.good luck with it there a pain but once you get them dialed in there awesome.

[70gtx]

6packman ,i also didnt want to hear the a/f screws on outter carbs would over fuel at upper rpms,
i opened thm to 1 turn and was worse ,i closed them to 1/2 and what a difference.thanks to all you guys help.
i was almost ready to send them to holley.
70CUDAS,if i plug the little vent on driverside of back carb it revs a little , but the other three little vents do nothing, what does this mean ,i pulled carb once more and shot carb cleaner through to make sure its open ,but still does it.