you installed a new power valve? what is the vacuum rating on it? both screws are for idle mixture. if you don't have a vacuum guage your gonna do more harm than good. when you get a guage hollar back and i'll walk you through it. sick

 

the power valve was rated at 4.5 (does that sound right)

 

ok ... here's how power valves work. when vacuum drops below the rated vacuum the power valve will open suppling the engine with needed fuel it's not getting through the normal vacuum process. this usually only occurs in WOT ( wide open throttle conditions ). if your power valve is rated 4.5 that means when the engines vacuum drops to or below 4.5 hg the power valve will open. you need to hook a vacuum guage to your intake. ( you can get one fairly cheap.) unplug you brake booster and hook it up there. then crank your engine put it in drive and hold the brake. if the vacuum drops below 4.5 hg the power valve is opening and it is loading up with fuel. what ever the vacuum is at this point ... ( let's say it is 9 hg in drive with the brake on. ) the general rule is whatever is your lowest point of vacuum during normal operating conditions divide that by two and thats the size power valve you should use. in my opinion 4.5 sounds about right. one thing to remember about holley carbs they have an unadjustable idle circuit on the secondary barrels that keeps the fuel in the rear bowl from getting stale. that's why it's so important to adjust the carb perfectly. just a smidgeon two much gas on the primarys and your loading up. thats why you must have a vacuum guage to adjust idle mixture properly. sick

 

ok thanks again i will run up to auto zone and get a gauge here in the next day or so, but now i cant even get the car started? what do i do about this?

 

since when? have you done anything else to it? is it flooding out? give me more info. sick

 

it stopped running last night it just stalled out and would not start again i think it could be floodin out but i havent pulled a plug yet.

 

ok i took it back apart and found the jets where pluged i cleaned them out and im going to try to start it here again in a little bit

 

hey sick,since we are talking about carbs ,i have a question.i have a 750 double pumper and it has the 4-corner air/fuel mixture screws.i've never had one with this(only the front two).i've been adjusting the front two ,never touched the back two.do you adjust these the same way as the front two.mine is running a little rich.i haven't messed with the jetting,i have changed the power valve.in drive i got 6" vaccum.i tried a 3.5,thought maybe i went to low so now i have a 5.0 in there.this is on a 454.surely its not running to much jet out of the box for a 454.the primary's are 72 and the secondary is a 78.give me your professional advice.

 

I don't know about professional advise ... i'll tell ya what i think. For one i think you need to change your power valve to a 3 or a 2.5. your never gonna get your air/fuel mixture right if the power valve is opening during anything except WOT. Have you used your vacuum guage while driving it around to see how many times your vacuum drops below 5hg? If not you might be surprised. Also i'm sure your aware that power valves blow at the slightest sneeze. Check them often. Another thing ... I'm not positive about this but i'm pretty sure the power valve channel restrictors dump fuel equal to a #8 jet. For optimum performance your secondary jets are usually 8 sizes bigger than the primarys. That way when the power valve is open your secondarys and primarys will be balanced with the correct air/ fuel mixture. So when your power valve is open your primarys are actually feeding fuel at the jet rate of an 80 while your secondarys are feeding at a 78. This might explain why your running a little rich.
You can try this method of four corner idle but, since your primarys aren't in correct proportion with the secondaries you may have to do a little more adjusting. Start out by putting a small piece of paper between the throttle butterfly adjusting
screws (Idle screws) and the stops, let the throttle close, now back off the idle screw until you can just slide the paper out, now go back in 1/8th of a turn. Do this on both primary and secondary ends. Now screw in all four-corner air mixture screws until they bottom and back out 1.5 turns. Hold the throttle open a little and start the engine, now ease the throttle to the stops, if it tries to stall do not hit the throttle, tap gently on the accelerator pump arm…. Did it get better or worse? This has told you what you need to know, if it got worse your still rich and you need to go 1/8th of a turn in on the idle screws. If it got better the opposite is true, so you'd
obviously open the idle circuit an 1/8th of a turn as your engine is looking for more fuel. This may take several times around the carb to get it right. Break out your vacuum guage ... keeping a close eye on your points of adjustment, check your idle mixture for optimum vacuum. If you still can't get the idle speed you want, remember you bumped the idle up 1/8th of a turn. Adjust each idle screw by 1/8th of a turn until you get the desired idle RPM, but you should be real close at this point. Good Luck. Sick

 

ok i got it to start, but wont idle. now it is spitting gas out of the carb where the air filter goes. i take it this means to much gas still or did i break somthing?