hey guys I am having some issues with making my car idle well.i have a trishield level1a built motor I am on my second carb .the issue I am having is when I set the idle which is around 850 to 950 rpms as soon as I rev it up it will start idleing at 1300 to 1400 rpms .when I put it in gear it will drop idle back down .also it makes your eyes run it is so rich at idle .I have backed the idle circuit screws in all I can and nothing seems to get better. I would greatly appreciate and help and advice .todd
$100 says rear blades are open to far Idle bleed is blocked Float to.high Need to take apart and blow all passages out, Set transiton slots to .020 or so All 4 idle mixture set 3/4 turn out Set float level with bowl off upside down in your hand Obviously check seat for contamination make sure cone is nice and smooth Turn idle speed screw till it contacts arm then put 1/2 turn on it Make sure throttle arm is returning to its stop smooth and clean after depressing pedal With above setting it will crank and depending on cam you may can lean idle mix out even more just remember you want it to idle off the mix screws notthe speed screw if its done ccorrectly the idle speed screw may not even be touching
I have floats set like they wanted 1/2 way up sight glass the idle circuit I have tried at one turn out I will try closing them up
AED has good quality control but I have pulled some interesting stuff out of new carbs b4 Id try lowering the front float myself also but it at bottom of window I assume the cam will produce over 6in of vac Have you tried putting some more initial timing in it then setting carb Also since two carbs have done this id look into your filtration
What about the ignition timing at idle? It sounds as if the carburetor is running on the mains at idle, the throttle blades are open too much, unresponsive idle mixture screws, etc.
Are your advance weights sticking in your distributor? You also have the inner and outer idle air bleed jets on the air horn of that carb. You may need to go larger to allow more air.
ok I talked to aed today the tech wants me to open secondary blades to lean it up .my weights are free and moving in dist .I have a feeling that it a timing issue but I am a little green with a timing gun.
One thing that could be happening is the timing is erratic. Not that hard to check. Start motor and note timing. Rev the motor and back off. The time should advance and then drop back to the original point. If the timing is hanging without dropping back then the engine will run at a higher rpm.
ya Doug that's what it does I can set the idle then rev it up then the rpms jump up and stay up ,I can put it in drive and that drops the idle quite a bit .if I then put it in park the idle will stay where I set it .
ok some I think I have made some head way I put a one spacer under carb there did seem to be a little catch somewhere.i adjusted the floats the front is in the bottom of sight glass the rear is about half way up.i put timing light on with vacuum unhooked it was showing the 3o degree mark around zero on the timing mark so I bump it up till it was steady at 12. it idles better when I rev it up it goes back to the set idle.i am not 100 percent sure on how I set the timing feel free to let me know what you think .it still smells pretty rich at idle but it does seem better I might try to open secondary blades slightly
If you lined the 30* mark up at 12 on the timing tab, you are at 42*, is the mechanical timing locked out? Both fuel levels should be mid way on the sight glass.
Sounds like you are getting somewhere. You cannot even think about the carb unless the timing is dialed in. Look up Larry's post on power timing. I am going to guess that you must have a performance cam if you are putting on a 1000 series Holly. If that is what you have then all the stock timing specs are out the window. Most cams like the TA 413 (example of popular cam) like 18 to 22 degrees initial timing with 32 to 34 degrees total. It's nice to have another 12 degrees of vac advance. Once you get the timing right I will tell you how to lean out the idle.
ok the wife came held rpm's at 2500 and it was holding just off timing marker when idling it's around 4 at 900 rpms I can't find my cam card but it was a 535 lift with 242/238 duration
That much cam needs at least 20 degrees initial to idle worth a damn. The problem will be your distributor. Most distributors have too much centrifugal advance built into them to run that much initial timing. If your distributor has 20 degrees advance built into it than the most you could set the initial with a 455 is about 14 degrees. So the next question is what kind of distributor are you running?
Hey Todd, sorry to hear your having issues.. Remind me what distributor you have in that deal, I looked at your invoice, and there is nothing for a distrib or any work on one, so you must have supplied it. Your cam is a TA 298H. With you standard (not dial back) timing light on it, have the wife rev it up till the timing mark stops moving, and line the 30* mark up on your romac balancer to the 4* mark on the timing cover. That is 34* total timing and what you want.. then let it go back to idle speed, and use the marks on the balancer (line up with the zero on the timing tab) to tell you how much initial timing is in it. Of course your going to unplug any vacuum advance canister if you have one. With that cam, I would run at least 20*, maybe more like 24-26.. initial.. that will help the idle quality tremendously. Sorry I don't remember more about it, it was a long time, and many motors ago. JW