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Offline ToniJ1960

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Re: Bad Idle..
« Reply #30 on: April 17, 2015, 01:58:22 AM »
http://www.ihpartsamerica.com/forums/carb-tech/3153-weber-carb-rebuild.html

 This picture shows using a vacuum pump to test the power valve diaphram.  If you dont have one, just push the valve in, hold your finger over the hole where they have the vacuum plugged into, and let go of the valve.If it stays down its ok if it doesnt the diaphram is leaking.

 If you cant see where that hole under the top half is, listen as you push the power valve in for air coming out from it.


 That test was ne I read in Petersons guide to the Pinto and I always do it when I get the no shut of from t he mixture screw issue.Its always been the power valve diaphram. Do the test yourself.


 But 14 inches is pretty low for idle vacuum. Have you got the timing set? The compression test is a good idea for sure.

 Another thing is, does your carb have foam floats or hollow plastic? If its foam you need to weigh it to see if its soaked up anything and heavier than it should be.If its the hollow one, you can throw it in a bucket of water or gas and see if it floats or makes bubbles if you push it under. They do get holes in them,I found an extra not long ago I was going to save until I found out it had a hole :(

Offline BrandyMB

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Re: Bad Idle..
« Reply #31 on: April 17, 2015, 11:35:03 AM »
Thanks for the reply ToniJ! I already have the exact same Rhino Ramps in the link you sent me.. Resend me the correct link please! LOL! Regardless, the power valve is new. I just had a kit put in the carb by a friend who builds racing carbs and knows his stuff. The floats are the plastic type and are fine. I do have a question.. I put a new timing belt in it and made sure the timing marks on the cam and crank were lined up properly. The other shaft got turned accidentally, but the only thing I can see that did was turn the distributor setting out of whack. I put it back to the position where the distributor was placed where I could get the timing right again. Book called for 6BTDC. Also I have a plate over the EGR mount and all vacuum ports have caps over them.
Mark

Offline Pintosopher

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Re: Bad Idle..
« Reply #32 on: April 17, 2015, 12:05:56 PM »
Thanks for the reply ToniJ! I already have the exact same Rhino Ramps in the link you sent me.. Resend me the correct link please! LOL! Regardless, the power valve is new. I just had a kit put in the carb by a friend who builds racing carbs and knows his stuff. The floats are the plastic type and are fine. I do have a question.. I put a new timing belt in it and made sure the timing marks on the cam and crank were lined up properly. The other shaft got turned accidentally, but the only thing I can see that did was turn the distributor setting out of whack. I put it back to the position where the distributor was placed where I could get the timing right again. Book called for 6BTDC. Also I have a plate over the EGR mount and all vacuum ports have caps over them.
Mark
I've seen no mention as to whether this car has had the head rebuilt or been apart to replace a head gasket and had the head resurfaced too. I do see that you have moved the distributor drive sprocket and reset it. Keep in Mind , if these three marks are not synched (because of the head possibly being resurfaced there is cause for concern here) it won't idle properly. having the engine marks on the crank pulley and cam sprocket in exact alignment is key to any adjustment (whether it be ignition timing, or  mixture adjustment).
 If you suspect that any engine work has been done, it's time to check this one off the list. This is relevant because those marks can be off enough to get the engine unable to run well at all at idle. Bad keyway indexing from the Factory has led to offset keys and even the much desired adjustable cam sprockets. This is a critical thing to check first before you go off on any more Fuel related adventures.
 How do I know? Just ask anyone here that races a OHC engine of any brand, especially an old Ford. There's a whole tuning philosophy to camshaft advance and it does have an impact , even on stock motors.
 A degree check of this system is in order.

 Pintosopher, as much as good timing will allow. ;)
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Offline BrandyMB

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Re: Bad Idle..
« Reply #33 on: April 17, 2015, 01:50:30 PM »
Funny thing is, there was no mark on the third shaft gear and believe me I looked. The car idled fine before I changed the timing belt and removed the smog crap. I also checked the timing marks before I pulled the ratty old belt. All good info, Mr Pintosoher. I dont think it would have idled well before all this if there was an issue with the head etc..?
Mark

Offline amc49

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Re: Bad Idle..
« Reply #34 on: April 18, 2015, 05:27:46 AM »
There is NO third shaft mark, setting the timing correctly and engine running at all means that is OK. Assuming timing set at BTDC not ATDC. A third shaft mark would actually be detrimental, you can put the shaft anywhere you want as long as the distributor is moved along with it to work right. Assuming correct point gap (points! HILARIOUS!) as well, gapping by hand is insane, use a dwell meter.

14 inches of idle vacuum IS low, I expect 18-20 on a normal good running engine.

IF car truly idled well before the belt and smog pulled then it is clear you messed up on pulling the smog. Several ways you can have a vacuum leak there for sure. That mixture screw HAS to work or you are p-ssing in the wind.

Offline Pintosopher

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Re: Bad Idle..
« Reply #35 on: April 18, 2015, 01:31:10 PM »
There is NO third shaft mark, setting the timing correctly and engine running at all means that is OK. Assuming timing set at BTDC not ATDC. A third shaft mark would actually be detrimental, you can put the shaft anywhere you want as long as the distributor is moved along with it to work right. Assuming correct point gap (points! HILARIOUS!) as well, gapping by hand is insane, use a dwell meter.

14 inches of idle vacuum IS low, I expect 18-20 on a normal good running engine.

IF car truly idled well before the belt and smog pulled then it is clear you messed up on pulling the smog. Several ways you can have a vacuum leak there for sure. That mixture screw HAS to work or you are p-ssing in the wind.
Actually the invisible "third mark " is having the distributor rotor pointing at the #1 wire location on the distributor cap, while the other two marks are aligned at TDC on the Compression stroke. The movement of the distributor body to set the Ignition timing must be roughly in the center of allowable range of movement. If the Belt is properly tensioned with the marks on the correct stroke, (cam, Crank and Distributor rotor) then this should rule out anything mechanical( timing wise)  except a head that has been shaved , thus the marks would be accurate. Beyond this, a porosity issue with the intake manifold, carb body, gasket sealing between the carb and head, or any possible leakage from any of the vacuum connections that were removed or capped. After this, a swapped carb would give an indication that all is in the original carb if it corrects the problem.
 The idle manifold vacuum should be higher but if it's steady, it may be pointing back at a leaking component. Achieving a higher manifold vacuum would be a better starting point.

 Pintosopher, looking for the elusive PZEV gnome every day when fumes arise. ;)
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Offline BrandyMB

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Re: Bad Idle..
« Reply #36 on: April 18, 2015, 01:40:00 PM »
Well Gentlemen, then I have all the components, ignition related, correct. All ignition parts are new, points set right too etc. I had the carb redone by a friend who builds race stuff and knows what he's doing, and had the motor looked over by him and another race guy I know and no one can see where a vac leak could come from. We sprayed stuff everywhere and the idle never increased or otherwise indicated finding a vac leak. When I put the carb back on, it started right up and idled so nice.. until the motor warmed up and the choke opened, then it went back to non-idle. I would put all the smog crap back on it if I had a hose diagram.. which seems to be non-available. Theres where the prob must lie. But every car Ive ever had in my entire life ran better with the smog crap plugged or removed. Im at a total loss.
Mark

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Re: Bad Idle..
« Reply #37 on: April 18, 2015, 02:21:44 PM »
Well Gentlemen, then I have all the components, ignition related, correct. All ignition parts are new, points set right too etc. I had the carb redone by a friend who builds race stuff and knows what he's doing, and had the motor looked over by him and another race guy I know and no one can see where a vac leak could come from. We sprayed stuff everywhere and the idle never increased or otherwise indicated finding a vac leak. When I put the carb back on, it started right up and idled so nice.. until the motor warmed up and the choke opened, then it went back to non-idle. I would put all the smog crap back on it if I had a hose diagram.. which seems to be non-available. Theres where the prob must lie. But every car Ive ever had in my entire life ran better with the smog crap plugged or removed. Im at a total loss.
Mark
Something is being masked here by the Choke butterflies being nearly closed. If the fuel supply to the bowl is adequate, and fuel pressure and pump output to the carb consistent, then a rich mixture is masking a lean condition . Even with all of the Smog devices capped or removed, it should idle at warm temp and the mixture screw have an effect.
 Out on a Limb here, have you run a Cold AND Hot Compression test, and the same with a leakdown test? If the expansion of the head is exposing a weak area of the gasket that coincides with the Choke (water temp controlled) you may have a temperature related head gasket failure causing a lean Hot condition. This doesn't mean that you'll find it by looking for anti freeze in the Oil, as it can leak to the outside of any part of the head.
 Given that resurrecting an engine that was sitting that many years unused, can cause all kinds of failures when restarted when you start the thermal cycling of the parts. I've had a vintage  Porsche run fine until it dropped two intake valve seats after a few runs while tuning it. It was a known issue amongst the Experts and should have been dealt with before reviving the car after 20 years idle. Unleaded gas only made it worse, even with a lead additive in the fuel. I was cautious when getting that one ready too, and it still bit me.
 There's more to be checked on this one before you dig further into the carb.
 
 My Bucket of Cents is running low here, more pennies needed :o
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Offline BrandyMB

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Re: Bad Idle..
« Reply #38 on: April 18, 2015, 02:35:53 PM »
THAT sounds like a distinct possibility. Ill do them tests next time im out at the shop. Wife is sick amd Im playin nanny for the moment lol.
Mark

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Re: Bad Idle..
« Reply #39 on: April 18, 2015, 02:47:41 PM »
THAT sounds like a distinct possibility. Ill do them tests next time im out at the shop. Wife is sick amd Im playin nanny for the moment lol.
Mark
I'm in the same boat with my wife right now, Super nanny! Can't get back to my VW  GTI ,chasin Evap System ghosts lol! :D
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Offline BrandyMB

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Re: Bad Idle..
« Reply #40 on: April 18, 2015, 06:09:23 PM »
You know, if I could find a diagram of the smog stuff, id put it all back on just to see.. 

Yeah, I have a 65 GTO and a 80 Vette that need my attention also and they're just gathering dust. But this little uncomplicated Pinto is making me pull out the rest of my hair, and I'm bald already..
Mark

Offline amc49

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Re: Bad Idle..
« Reply #41 on: April 20, 2015, 08:09:53 PM »
Waste of time, all that's needed there is to plug the vacuum sources you unplugged at that time and the cars run forever with no smog, I did an MII '74 model same engine and it ran forever, took a 6 inch hailstone storm to take it off the streets in '95. No magic there, I'd bet a million on carb internal error or fuel supply issues there. Why all the vac leak testing showed nothing but still a hundred other places you can error there. Your race guys should well know that, I built plenty of race carbs and motors myself. That little carb there often stymies race carb guys as Holley carbs are so simple that 1st graders understand them, not so that carb.

And, IF car was running fine before then why did we mess with the carb to begin with? FYI, I have heard that 'it ran fine before I...' line so many times it goes in one ear and out the other on a 6 lane freeway, often it turns out to be totally false. NO INSULT INTENDED AT ALL BUT when one says that they lock themselves into not weeding out all other choices by the people helping and often results in the poster NEVER getting the problem fixed. I've seen it a 100+ times and why most GOOD repair guys often ignore everything a person says about a car and previous conditions so he can start with a clean slate to easily figure out the problem. Sorry, but often the ONLY way they get fixed.

And why compression test keeps getting mentioned..... ...........the   car is a '74 with no induction hardened valve seats, if the 14 year timeline is right then it could have been driven for years after all fuel went from low lead to true 100% unleaded around '93 or so and the valve seats could be dead as a doornail to have the car not run right at all. The same MII I reference above began to have severe valve problems every 10,000 miles after the fuel changed. Another valve job and back to running fine until they die again. Idle going to crap is what shows up first to most novices, power will drop off before that but low enough amount  that most will not notice and claim 'it runs fine', sound familiar?

Offline BrandyMB

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Re: Bad Idle..
« Reply #42 on: April 20, 2015, 08:23:34 PM »
No insult taken, my friend. I know exactly where youre coming from. Im retired Systems Analyst and I used to go out on network/computer issues and ALWAYS started over from the beginning regardless what the user told me he/she did. I tend then to agree with you too. The engine never seemed to have the getup and go I would have expected it to have, when I did say it was running right. Smog systems (here in CA) always dog a motor down so I removed the AIR system right away. Dont need to be driving that pump. Friends suggested I ditch the rest so I did. Now that the wife is getting better I can spend a ittle more time messing with the car. I intend to do compression checks and I have a bud who has a leak-down tester. Also I would just love to ditch that complicated carb and install a simple straight forward one. Any suggestions on a not break the bank bolt on carb? Oh this is such fun. I have a 65 GTO, 80 Vette and a 75 CJ5 and rebuilding them never gave me 1/10 the headache this Pinto has!
Mark

Offline amc49

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Re: Bad Idle..
« Reply #43 on: April 20, 2015, 08:59:19 PM »
Original carb is actually the best one if you do not want to launch into rejetting and things like that. The Ford 2 barrel 2100/2150 used on the bigger cars often used but you must set up the carb yourself. And if you can't find the problem here in carb, then same problems with that one although less passage issues with clogging there. This carb is simple as well, just not many used to the ways it does the same things all carbs do. I grew to like it as I was very familiar with it but then I've done carbs all my life so none of them are an issue.

If wanting to go to the other carb Dick here onsite could probably help with that.

For sure yank the small entry filter if keeping this one (5200) and patch in a bigger inline one with rubber hose on both ends as adapters. That small filter can clog in five minutes of running if they use ethanol in your area and your steel tank will be full if superfine powder rust from it. You need to pull the idle feed restrictions that both screw into the carb top and positively make sure the very small port in them is fully open. IIRC, the actual jet there simply inserts inside the outer screw cover that threads into the carb top. Jet has holes through the sides and one small one right down the middle. Thinking you can pull those without removing carb, at least the driver side one. Those feed the idle fuel.

My younger brother was a national network systems analyst for McKesson-HBOC before they cut back all the 'overpaid' help, they replaced him with 3 other people and still lost their butts by letting him go. I probably picked up some of my outlook from him as well.

Offline ToniJ1960

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Re: Bad Idle..
« Reply #44 on: April 23, 2015, 06:29:50 PM »

Offline amc49

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Re: Bad Idle..
« Reply #45 on: April 23, 2015, 09:45:38 PM »
Post #6 in that thread clearly shows one of the idle feed restrictors, the brass colored screw at the top. It is really just a holder, the restrictor is pressed inside it.

Power valve vacuum leak issues can be problematic, while a greater leak will lean out the idle, a smaller one will richen the idle when the valve then slowly moves down to open the power valve, like adding at least five sizes larger main jet and the engine goes rich even with a vacuum leak since at idle the main jets are unused. As the vacuum leak gets bigger though it will overwhelm the richness to then go lean. A see-saw effect there.

Knowing how to take apart and reassemble a carb is not the same as knowing what every last single port and hole does in fine detail, and how to mod any of them when the carb does not do what you want.......... ......... big difference there. Anybody can change jets or power valves, it's when you start drilling holes bigger or more of them and things like that you'd best know what you are doing.

Offline ToniJ1960

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Re: Bad Idle..
« Reply #46 on: April 23, 2015, 10:23:20 PM »
 Am I wrong in thinking that mixture screw pretty much has to be able to cut off the gas/air mixture unless its the power valve lettting more gas through? Thats what I was told a long time ago by the guy who rebuilt my motor. The description on  this site makes me think its true as well.

Offline Srt

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Re: Bad Idle..
« Reply #47 on: April 24, 2015, 03:50:20 AM »
all my experience says i agree...


"...[size=78%]You need to pull the idle feed restrictions that both screw into the carb top and positively make sure the very small port in them is fully open. IIRC, the actual jet there simply inserts inside the outer screw cover that threads into the carb top. Jet has holes through the sides and one small one right down the middle. Thinking you can pull those without removing carb, at least the driver side one. Those feed the idle fuel.[/size][/size][size=78%] [/size]
[/size]
[/size][size=78%]these do have a lot to do with how [/size]the[size=78%] car can run.  have had to start from scratch, bone stock, many times in the past to get BACK to a baseline to, once again, begin a diagnosis[/size][size=78%]
the only substitute for cubic inches is BOOST!!!

Offline BrandyMB

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Re: Bad Idle..
« Reply #48 on: April 24, 2015, 11:53:39 PM »
Well, it idles! I took off the egr plate and cleaned and changed the gaskets, also took the carb back apart and went thru it with a magnifying glass. I took everything back apart again and blew out every passage and place fuel could go. It appears that there may have been a little piece of crap in the idle jet. I couldnt blow thru it nut anyway, I put it all back together and it idles and the mixture screw has some effect.

So I took it out for a ride and I have a new strange issue. It doesnt seem to be getting enough fuel maybe. What was odd, I push on the gas and it gets a some nice power while the gas pedal is moving down, like the accelerator pump is feeding it, then it tapers off if I hold the gas steady. I can pump the gas pedal and it gets nice shots of power as I do it. lmao! It runs kinda flat though until I floor it and the other barrel opens up and it picks up nicely.

What may I have screwed up??

Mark

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Re: Bad Idle..
« Reply #49 on: April 25, 2015, 12:48:51 PM »
Making some headway at last I see. Sometimes you never see the offending clog but you'll know when it is gone. Yes, now you know about the idle passages, may be looking at power valve issue now if it only messes up at demand for more power.

If you get to the problem but then punching gas pedal to work accel pump makes it better then most likely lean without the pump shot and possibly a power valve issue. Under the valve itself that screws into bottom of fuel bowl is another small restriction in the sideways passage that because of being so low often clogs to make power valve not work even if the piston and valve moving up and down like supposed to. Sort of the main jet for the power system if you will.

Yes on earlier non-smog carbs the idle mixture screw should totally kill the engine when screwed shut, once past like '78 or so though they may only make engine slow down but not die, the later even leaner carb settings killed some of the screws' effect but not all, you should be able to get some at least slight effect both too far out and too far in, some won't show much at too far out though as they were not set overly rich any longer like they used to be. The engineers were narrowing the tuning envelope there since so many mess with things they should not be touching, the EPAs' 'tampering' thing. Why they began to get limiter caps.

Kicking secondary open to make it better seems to point at the power valve. The valve feeds the primary only and is part of the main systems' fuel at full power, with it off like downjetting 5-10 steps of main jet depending on the carb.

Offline ToniJ1960

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Re: Bad Idle..
« Reply #50 on: April 25, 2015, 07:44:22 PM »
 All we can do is make wild A#@ guesses but heres a scenario I had.

 If the vacuum is too low to hold the power valve actuattor up off the valve, and too much fuel is getting through so that the idle screw cant kill it, and it was somehow all fiddled to make the car  idle that way, then theres no power enrichment possible as the actuator would already be holding the valve open.

 Or if theres a vacuum leak inside the carb ie ruptured pv diaphragm or leaking where the top meets the bottom of the carb. Vacuum is supplied through the bottom casting to that channel that carries it to the pv diaphragm.

 The first thing I would do still is take the top half off turn it over push  the actuator in, put my thmb over that hole ( see picture 8 where its marked with a dark stain) and if the actuator doesnt stay down until you remove your finger or thumb from over that hole, the diaphragm is ruptured or not sealed right inside its housing.

 I got a kit for my carb and it did come with two different diaphragms and I know theres a long and a short sized actuator.

 Also, on the diaghragm that came with that kit, the base shape of the diaphragm was a little off and took carefull trimming or installation I cant remember exactly but I think it had something  to do with the area around where the screws went in.

 Now another time I needed a diaphragm for the choke pulloff, went to this carb shop that everyone touts locally. I bought the diaphragm put it in ran great a few days later it didnt. I took it out it had stretched. I looked it over and it seemed to be a lot thinner material and didnt have the threads or fibers in the rubber. Maybe it worked on a Chevette but not on a Pinto.

Offline BrandyMB

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Re: Bad Idle..
« Reply #51 on: April 25, 2015, 08:03:18 PM »
Toni,
thank you and all of you for your replies. Im in the middle of a job so I cant write much at the moment, but where is picture 8?

Mark

Offline ToniJ1960

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Re: Bad Idle..
« Reply #52 on: April 26, 2015, 11:17:51 AM »

Offline amc49

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Re: Bad Idle..
« Reply #53 on: April 26, 2015, 02:09:59 PM »
' The first thing I would do still is take the top half off turn it over push  the actuator in, put my thmb over that hole ( see picture 8 where its marked with a dark stain) and if the actuator doesnt stay down until you remove your finger or thumb from over that hole, the diaphragm is ruptured or not sealed right inside its housing.'

X2, I do the same.

Take note when swapping different year parts that the later PV is metered out rather than all on or off with no in between, you CAN swap some of those parts but the vacuum source changes location, they while going to the metered one were setting up the engineering for the true feedback carb which at first used the PV system remnants to modify the carb signal pull to the main jets electronically . The later type PV will be on carbs with the different top cover that kicks out a new notch in the aircleaner base, the two bases do not interchange. The power valve itself will have a gradual metering rod type stem as well instead of the dead flat cutoff part of the poppet there. The spring rates are different too, one has to move slowly, the other moves quick when needed. The later top has the advantage of a setting screw in it to then be able to exactly set the power valve top vacuum piston too. So you can set the exact timing of the come on of the metering. I mixed and matched a few of those parts to pretty good result there for a while.

Offline BrandyMB

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Re: Bad Idle..
« Reply #54 on: April 26, 2015, 02:19:56 PM »
Im about to go out to my shop and pull the lid and check out the PV as you folks have recommended. The PV is new in the crtb when it was kitted her the other week, but may be on incorrectly or vacuum leaking. Ill also check the passage under the PV valve in the bottom of the carb.

Lol its almost getting to the point for me to just up and buy another carb for it and leave the last two hairs in my head not pulled out..!
Mark

Offline BrandyMB

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Re: Bad Idle..
« Reply #55 on: April 26, 2015, 03:33:37 PM »
I just pulled the top and the PV is perfect and so is the valve in the bottom of the bowl. I pulled out the main jets and they say 35 and 42. Would those be right? I can't seem anything else of note..

Offline BrandyMB

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Re: Bad Idle..
« Reply #56 on: April 26, 2015, 03:37:24 PM »
Oh by the way, now when I screw the idle mixture in, it kills the motor.

Offline ToniJ1960

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Re: Bad Idle..
« Reply #57 on: April 26, 2015, 05:07:54 PM »
 Is the vacuum idling still 14 inches? I wonder if thats enough to hold the pv actuator in. Do you have a vacuum pump like a mightyvac?

 The timing is verified?

 You can set the mixture with your vacuum gauge watch the vacuum as you adjust the mixture screw and try to get it to where the vacuum reading doesnt drift up and down.


Offline BrandyMB

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Re: Bad Idle..
« Reply #58 on: April 26, 2015, 05:52:58 PM »
15 inches is enough to keep it open. with my mityvac only took about 5 to pull it in  i put it back together and drove the car this aft. runs better than before. ill do some more fine tuning tomorrow and see if i can get it beter. thanks!
Mark

Offline amc49

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Re: Bad Idle..
« Reply #59 on: April 27, 2015, 12:38:33 PM »
Usually set to open under 10, like 8 or so.

Old tuning half-rule there, you pick a number at half the idle vacuum for power valve if you have choices of them like Holley, which uses 8.5 in most of their stock replacement stuff.