ever since i put the Holley 600 on my 13b, the power seems to drop right off above 4500rpm or so. the secondaries are mechanical now with the 'screw trick'

when i physically push down the butterflies in the secondarys they only move about 1/8" if that. i've searched around and havent really found how to fix this problem, if it is a problem? just many people saying to change fuel filter, change jets, etc. but those really shouldnt be my problem

there is just no play in the secondaries, something is stopping them from opening fully.

any idea's?

- Murray

 

if you just push down on the secondaries they will not open all the way cause the linkage will not let them unless the primaries are open. best way to check for full thrittle is to have somebody step on the pedal for you. you can do it by yourself just opening the main linkage all the way, but who knows if the pedal is adjusted right.

 

ya, i tried pushing on the linkage briefly, i'll have to double check that tho. at the time i think it still felt "stuck"

just weird how the power really drops off at 4500rpm. the car hauls *** up to that, i wonder if my FPR could be at fault, i may just try running without it and see how that goes.

as for adjusting the pedals, i did adjust them right after i put the holley in, im using the 12A throttle cable which seems to fit up perfectly even though this setup is for a 13b.

 

The butterfly should be vertical when at WOT. I think you need to adjust something to get it to open with the primaries.

 

"something"? ya this is the problem ive come across via searches on the forum. lots of people saying to fix your secondaries but not much explanation on how to actually do so

i have the rebuild manual which doesnt cover this problem either. im thinking maybe the accelerator pump is seized? (just a guess) i really dont know.

any general ideas would be greatly appreciated.

 

I know on the Nikki, that the secondaries are opened by a few linkages. Possibly yours is set up the same way and some of them are bent "out of proper shape". Just an idea, not familiar with the holley carbs.

 

the linkage is pretty simple on the holley. i pulled it open a few times to watch how it works, also pumping the pedal inside the car (while adjusting the pedal height, etc) and far as i can tell i am getting the throttle linkage fully opened.

the actual butterflies just dont seem to want to go wide open is what i dont understand.

i was just looking at this today but perhaps i'll look a little closer to be sure. thanks Ian

 

ok, you have got me stuck here. if you have the 'screw trick' and you adjusted your pedal right you should have the secondaries wide open open when you do do that. if they are not the pedal is not adjusted to your carb. now if you have pulled on the linkage to see how it works and it's pretty simple, sounds like it worked fine. was that befor the 'screw trick'? and is this a raceing beat preped holley or just a box holley? brand new , used, or been sittin on e-bay? the problem with this question is that there is a wide variaty of problem it can be and to want a specific answer, well we need specific starts. just by your first post, it could be rust on the linkage, linkage bent wrong, screw not right, accelerator pump stuck, pedal not adjusted, vacuum secondaries stuck. too many possable problems. good luck.

 

ok paradox, the linkage from the primaries that work the secondaries, rides along an arched slot. where in that slot is ur screw? it should be about halfway or so. u want the secondaries to start opening when the primaries get atleast halfway open.

 

well. finally got the secondaries opening and holy stink does the car haul *** now!

i watched the linkage moving it around and such, then moved the screw up a bit higher until it was pressing enough to open up the secondaries. tightened it up, went for a spin and wow. driving without secondaries for so long i didnt realize how much power i was missing out on.

one thing i did notice is i had to put the screw a lot further than half-way. check the pic.

thanks guys!