[LXS]

Well I've been contiplating buying a rear conversion kit for my Holley 750VS 4160 3310-6 carb, that way I can change the rear jets and get more accuracy....along with that, I'm planning on buying a Vacuum secondary diaphragm quick-change housing kit. Now before I do all of that, I need to know if it's a "big deal" if my idle adjusters for the air/fuel don't work. I know they don't make an impact on performance, and have no affect while driving, so does it matter that when I close or open both pins, nothing happens? I do have a Holley rebuild kit that I bought a couple months ago, but I didn't have the time to do it since my car is my daily driver. Now since I'm back off work due to my back injury, I figure if I have to, I can rebuild my carb if it needs it. So basically what i'm asking, if I lost anyone in my ramblings is....does my carb need to be rebuilt becasue my air/fuel adjusters don't seem to work? Thanks in advance everyone

 

[Pat Kelley]

If the idle doesn't respond to them, the most common cause is a vacuum leak.

 

[LXS]

Hmmm....I wonder where I could have a vacuum leak? I know it sounds stupid, but where is a "common" place to have a vacuum leak that would affect the idle adjusters?

 

[baddbob71]

Your idle air bleed circuits are clogged, you'll need to clean them with carb spray and maybe a torch tip cleaner or just soak the carb when you rebuild it. The air bleeds are small brass jet like looking orifices located in the main body. The outer ones are idle circuit and the two inner ones are main circuit. If the mixture screws have no response when turning this is usually the problem. Also check that your air filter is sealing good to make sure it doesn't happen again soon. Buy carb spray with the small tube wand and direct the spray pressure into the orifice.

 

[LXS]

Thanks Bad Bob....so then do I just take the "pins" out and start spraying carb cleaner thru the orifices? Do I do this with the car on or off? I have a couple cans of carb cleaner, so if it's as easy as your saying, I'm gonna do it tomorrow morning.

 

[baddbob71]

No, not where the pins go. Look in the choke tower and you'll see 4 small orifices along the inside front edge of the choke tower, the two orifices related to the idle circuit are the ones closest to the right and left sides. the center ones are for the main circuit, clean all of them. You could shoot into where the adjustment screws go but it would just blow out through the circuit and into the intake below the throttle blades.

 

[427L88]

Hit them with carb cleaner, and then I also use a small can of compressed air and hit 'em again. All four.

Yes, its a big deal when your idle does not respond, it means something is messed up and not working right. Hope its this simple fix, but you might need to dig deper. Get the carb running right before you start swapping things around , IMHO.

 

[LXS]

Thanks a lot guys, I'm gonna spray it with carb cleaner in a little bit, gotta wait till breakfast goes down Right now I don't have any access to compressed air. So I'll just have to hope that the carb cleaner does the trick.

 

[70_FathomBlueMalibu]

Is it possible that he has too much of his idle transfer slot exposed?

There should be between .020-.040 (basically look like a square) showing.

Pre-setting the slot and the floats are the first things I do.

 

[LXS]

Ok well, I sprayed carb cleaner in those orifices. I also sprayed some in the rear ones just in case. Well, after spraying them I played with the adjusters. It didn't really react as it should, although I noticed when I was close to having them all the way closed, the idle seemed to go higher. At one point, while adjusting the driver's side, the motor turned off. Pretty much the same thing happened with the passenger's side. By the way, which pin adjusts the air and the fuel? Driver's side is ___ and passenger's side is ___. As for revving it in park, I really didn't notice any difference, if anything, it seemed to rev a little "easier" but then again, that could have been because I tighted my alterntor and power steering belts. I don't know how to adjust the floats, I just know that you're suppose to turn the big screw clock wise or counter clock wise, but I don't know which turn does what. I don't have my carb books with me right now, so I can't refer to them. Thanks a lot guys, and please keep the info coming

 

[superwrench]

ive been workin on carbs for the past 17 years id say its your power valve 100% no question remove front bowl screws then remove bowl and the 1/2 thick metering block behind it you will see a 1 inch plug called a power valve remove it the are little tiny numbers on it replace it with the same design and a new bowl & metering plate gasket .stock your carb comes with a #6.5 power valve

 

[LXS]

I don't have a vacuum gauge to test to see which power valve size would be best, but, would going with an 8.5 make my motor perform better? I do remember somewhat in reading one of my books, that a 6.5 power valve is good for stock motors, and that an 8.5 or even a 10.5 power valve is best for performance/racing motors. Of course it did say that to know what size is best, you need a vacuum gauge. Since my motor isn't an all out racing motor, and it's definatly far from stock, would an 8.5 be best? Thanks!

 

[superwrench]

floates adjust rather simply here goes : park car on a level surface no hills then remove 2 brass plugs on passenger side of the carburator if fuel is running out of the holes or only one adjust them slowly loosen top scew 1/4 turn while engine is running of course or electric fuel pump is on and the 5/8 nut under neath you would turn clockwise until you see it stop dumping out when it does give the car a little shake side to side barely if you see it come out ever so slightly your mint hold the 5/8 nut and turn that screw in to lock it back up and your done.. very simple and dont forget to place 2 rags under them screws on the side

 

[superwrench]

power valves are picked by engine vacume if you have a reading of 15 to 16 inches of vacume you divide that number in half then subtract 2 so you end up with 6 to 6.5 ... the more cam or compresion you have the less vacume you would have wich means the less number power valve you need ... example #2 a race motor with 8 or 9 inches of vacume you want a 4 or 4.5 # power valve

 

[LXS]

O ok, so I guess I had it backwards

So then a 6.5 would be "ideal" for a street/strip motor...of course depending on engine vacuum.

 

[superwrench]

yep you got it now get to work and get it fixed

 

[LXS]

Well I tried me best to adjust the floats. I know you said it had to be on a level surface, but unfortunatly, I live on streets that have slight hills. My street, and where my car is parked, is pretty much as flat as it gets.

On to my "adventures."

My carb didn't have any bronze things, just a screw on the front and rear bowl. I had to read your response a couple times becasue it almost sounded to me like you were saying to take out the bronze filters from where the feed line hooks up to........unless that's what you were really trying to tell me??? DOH!!! Oh well, anyways, as soon as I removed the screw for the front bowl there was gas pouring out. I loosened the nut and turned the screw clockwise. Only thing is, is it suppose to squirt gas from the nut/screw on top of the bowl? Anyway, I kinda played with it and I had to raise my idle because my motor was shaking too much to see a small steady stream of gas pour out. Instead I had gas pouring everywhere. Well I figured I'd adjust the rear to. Pretty much did the same thing. I'd loosen the nut, turn the screw a little, tighten it up, rev the motor to see how it responded. Once I felt it was "ok" I got in and drove forward and reverse where I was parked. I know the real test is driving around but over here, as soon as you turn you car on, let alone move it, people are practically sprinting out their houses to take your parking. Anyway, I did notice it seemed like it responded much better. I noticed that when I'd stab the throttle harder then usual, my tires would chirp a lot quicker then usual. Another reason I did go drive around is because earlier, while I was spraying carb cleaner in those little orifices, I adjusted both my alternator and power steering belts. Well it turns out I broke my power steering bracket...my second one. I gotta figure out which or what type of bracket to use. I'm using an Edelbrock Victor series water pump, which doesn't use that long bolt that the stock type set up uses with the power steering bracket. I have one small bolt holding up the bracket, the one that bolts onto the water pump. It just hangs there, and it finally cracked and broke off. Anyone have any ideas as to fix this problem? I know if I were to buy aftermarket brackets, like the ones that come with March pullies, that'll fix my problems...but I don't have the money to spend on pullies and brackets. Thanks a lot guys for your responses, please keep them coming, and I'd appreciate any and all help with my power steering bracket also

 

[superwrench]

the screws are on the passenger side of the carb about a half inch round and they are flathead type (screwdriver)they are called sight plugs just made for looking at the fuel level.. never i repeat never attemp float adjustment unless you remove them first and if you see no fuel come out of them the the 5/8 screw on top ya wanna turn counterclockwise till you see fuel trickle out with a shake of the fender and also if the car is not level you cannot adjust go to your neighboorhood grocerystore and use there flat parkinglot... re read post again and repeat .

 

[LXS]

Ok. Just a few more things...

#1. When I loosened the nut to adjust the floats, of course that was after removing sight plugs, is it normal for fuel to start spilling out from the float adjusting screw/nut? Because I had gas spilling out from it, and of course also from the sight plug hole.

#2. My motor is somewhat "radical" and no matter how high or low I set my idle, the motor is constantly jumping and shaking. I don't know how to really "judge" to get the fuel to trickle out the sight plug hole...since the motor is jumping and shaking, there was a lot of gas spilling out the hole.

#3. When I loosened the nut to adjust the floats, the screw only turned clockwise. I don't know if the person who rebuilt it (about 5 years ago) left it "closed" or what. I tried to loosen the nut and turn the screw counter clockwise, but it didn't move. Then when I tried to loosen the nut more, figureing it could still be too tight, I had fuel spilling out from beneath the nut.

#4. Is it normal for the float adjusting nut to loosen on it's own? After removing the sight plugs, I went to loosen the nut so that I can turn the screw. Well the nut was loose. Not "finger" loose, but loose enough where it took very little effort to loosen/tighten the nut.

I believe that's it for now. I probably won't get to mess with it untill Monday. Thanks a lot and please have patience....I have little to no experiance tunning carbs. Thanks again!

 

[superwrench]

look bro its ascience and if you spend time caressing it like a fine woman it will respond and also with the floats set high like they are it will idle ruff period i dont care what you do .. so take your time and repet and also they will turn couterclock wise use the 5/8 wrench if needed but if they are high ie: gas running outa the sight plugs on the side you need to go clockwise before trying this give a nice tap with the back of the screwdriver on the screws on top of the front and rear bowls and remember it must be on dead level ground period no exceptions perfection takes time . **** last month i couldnt even turn a computer on now i can alost type 10 words a minute hahaha im learnin slowly but surely ////goood luck