I have this holley 4010 750 on my 455 that idles fine in park,screams at wot,but just doesn't like to idle in gear.It will stall if I don't feather the pedal.What can cause this? I've tried this carb on another vehicle with the same results. I don't really know what's been done to the carb. Is it possible the carb was jetted to race ,if that makes sense?
Hi Tom, I don't know if you still use a dashpot on the intake for controlling the idle? I noticed a huge difference in controlling the idle from when I switched from my old dashpot to the optional 1971 idle electric solenoid.
check the major carb websites tech sections. holley, barry grant, and edelebrock have excellent troubleshooting sections with videos. sounds like not enough fuel at idle. good luck
Its gonna be an adjustment issue, adjust it just like holley says to do and most of the time a carb will do fine.....look close at the idle transfer slot relationships... and the idle mixture screws.... and the dashpot too....also look for a vac leak in something besides the carb.....
Im not too familiar with the 4010's. Im a 4150 guy. I think Doc is on the right track. You probably have the primary tranfer slots too exposed. Try lowering the idle from the idle screw, then opening the rear throttle plates up a little. If its an older style Holley, there's an upside down screw on the right side. I made a bent screwdriver to adjust mine. I think the newer Holleys corrected that bad design.
Jason, I am wondering if he has ign. timing issues too....pard you might try bumping the timing up some .....or set the engine up so that you have full vac advance at idle.....
i think doc is right. i have always been taught to start at the dist. first. then adjust the carb when the timing is right. jim
No,timing is fine.Like stated in the original post,same results with this carb on a different vehicle.I've tried adjusting it,and just when I think I got it,she gets erratic on me.Here's a short video I found of the idle. http://s18.photobucket.com/albums/b111/tt455/?action=view¤t=blkgsst1spgs011.flv
i know you said the timing is fine but do you have points on your car? if you do i would check the dwell first. it does sound like its a mixture issue though. put your hand on top of the carb like you are choking it out. if it idles fine then you are running to lean.:beer
Well, I listened to and looked at the video and It still seems like the timing is slow, not much , but still slow..... and.... or the carb is loading up some..... or a combo of both....o No: What I was trying to get to is this.... is the vac advance hooked up to straight manifold vacume , so it get advance at idle , or is it set up on ''ported'' vacume so that it gets no advance at idle....I think that it would do better with straight vacume..... and then adjust the idle mixtures and the idle rpm level.....:idea2: :idea2:
What power valve are you running? The carb probably has a 6.5 in it. If you have around that vacuum reading (6.5 in/hg) at idle, that could be part of your problem. Try putting in a 3.5 or a 2.5 PV in and see if that doesnt clear up the problem.
Sounds like a vacuum leak to me. Having the engine idle at 1100rpm's unless you have a radical camshaft. it shouldn't need to be that high. Try an unlit propane torch around the manifold and carb to see if there is a leak.
Jason, that is also a possibility,,,, I listened to the vid and could not hear a real lumpy cam, but the idle is pretty high.... and my hearing is not what it used to be after working on those locomotives for years....yep, ck out the power valve, compaired to the vac level..... but, guys, he said that he tried the carb on another engine and it did the same thing....could be a busted or dry rotted power valve though.... it is going to be something simple like that....
Holley power valves also blow at the first intake backfire. Most times its the PV easy fix. I agree and put the vac advance on ported not intake. How much vaccum are you getting at the intake?
i agree. you dont want any advance at idle. if your holley is an older one then yes i would agree about the backfiring blowing out the power valve but the newer ones dont do that any more....:beers2:
