Okay stumped again, and quick rundown: I have a 1981 Ford F100 with a 302 and 3 speed manual transmission. I have a Holley carburetor, with an edlebrock high rise intake. Here is my problem:

Was running rough on cold start, didnt run right when warm, hesitation, etc, and was last rebuilt 20 years ago. So I was told to rebuild it. Went through this carb with a fine tooth comb, found all kinds of issues that would cause rough running. What I have is a 1850-3 holley 4 barrel double pumper with a manual choke(which I removed since it was seized up anyway). I do not know the power valve size since it was not marked, but I put a 6.5 back in. The jets are both 66 on primary side and there is nothing on the secondary except the power valve. I have replaced all the diaphragms in this, and all the seals I could find and now here is what I get: Truck started fine after it got gas, then once it started to warm up it shut off. I had to pump the fuel to get it to start, then it would die. Pump the fuel again and hold the pedal down until it hits like 2000 rpm and it would run, hear a few pops now and then from the tailpipe but other than that, wide open throttle burst are quick and snappy. No black smoke so apparently the power valve is right on the money.

What I have done, started the adjustment screws a 1 1/2 turns out, closed the screws completely and turned them out 1/4 turn until I reached 3 complete turns out and still no start at all at every interval. WHEN I did get it to run, I checked a vacuum gauge connected to the diagnostic port at the bottom of the carb and it was pulling ~15 inches vacuum. So now we have the basics, lets start from there. Anyone got any ideas for me?

 

Right after you rebuild one of these carbs, the fuel bowl levels need to be checked. Pull the site plugs and see where the fuel level is front and back. Having said that, they should be in the ballpark if you set them during the rebuild, so when it dies on you, I would take a flashlight and shine it down the carb throat and push the throttle wide open(engine off). You should see two strong streams of gas pour into the engine. In your case if you do have a double pumper, you should see 4 strong streams pour into the engine.

If you don't see fuel, you have a fuel delivery problem. If the fuel lines have been modified/re-routed, or a dual exhaust has been added and it's in the vicinty of the fuel line, that would be suspect. Or it could simply be a bad fuel pump, if you don't have fuel.

 

@franklin2, Thanks for the info. I set the floats while the carb was off tried to set it lower than normal to prevent a floodout. I do know that I went and messed with it a little while ago, and finally got it started and idling a lot smoother. Here is what I have now. Idles pretty decent, and I am pulling around 15-16 inches of vacuum (I am wondering if I need to increase the power valve from a 6.5 to maybe a 7.5) I do not have a double pumper now that I realize what that is, I am only going off what grandpa says it is I have very little knowledge of carbs. But I do have the accelerator jets on the primary pumping fuel real well when you apply the gas pedal, so there is plenty of fuel. I went to check the fuel level while it was running, needless to say, I set it too high cause it is pouring out of the sight hole. That will be the next thing. I did take it for a spin down the road, and as long as you got the pedal floored, it runs great. When you stop and try to do a U-turn, and ease on the gas, it wants to stall out. Idles great, screams when it is floored, but cruises like crap.... Too much fuel?

 

Yes, you know the level is too high, but you don't know how much. If you set the floats during the rebuild, it may be the float needle has a piece of dirt in it. All it takes is a little chunk of rubber hose to do it.

Since you rebuilt the carb, I guess you know you can pull the complete needle assembly out and check it for dirt, oil the o-rings and re-install it with the carb on the engine(I guess it depends on what holley you have, some of the new ones you can't). Also check the rear bowl.

If it has a piece of dirt, the fuel can get so high it overflows and pours fuel down into the engine, making it stall out all the time. Sounds like what is happening to you.

 

Hey Franklin2, you were right! I pulled the truck into the garage, and checked everything over real good before I pulled the Carb again and what I found is, the fuel level were apparently set so high, that even when I went to loosen the adjustment screw, fuel poured out the top of the bowl. I got the level set, but the crazy part is, the truck is running crazy rich and if I adjust it per Holley recommendations (using tuning that has highest vacuum) then it is setting the adjustment screws about 3 full turns out. But even when the engine is up to normal operating temperature, it still puffs smoke out the tailpipe (like it would when the carb is on full choke). I will inspect the plugs, distributor cap, and rotor button, and make sure things are top notch since things has been running funny since last year. Only problem is, while I was trying to change the belts, I broke a bolt that holds the alternator bracket in place. So after some.... engineering (while cursing insanely) I fixed it, but I need a shorter belt now. Thanks for all the help you have given Franklin, you seem like you know a lot about some carb work !!!!!!!!!!

 

Okay, something is still wrong here. Got the carb set properly per holley, the floats set just right, changed the belts and went to take it for a ride. Put it in first and it seemed like it was chained down to something, I had to REALLY give some gas to it to keep it from stalling out on me. I am just about the throw the towel into the intake and light it on fire. Worst part about this is, once I get it out on the road and throw down on the throttle it will pull posi until I switch it to second gear, dont get it.

 

What is "got the carb set properly per Holley" mean? I have found the float level works best when there is no fuel running out of the site plugs, and if you put your weight on the fender and shake the truck, fuel just sloshes out of the site hole. That's where I have found they run the best.

Go ahead and set the idle screws for the best idle. If you end up 3 turns out, that is a clue you are sucking air somewhere, and you are having to turn the idle screws out too far to compensate. Also, make sure you idle is down around 600-800 rpm. If the idle is too high, the idle mixture screws will have less affect.

Did you mess with the secondary stop screw for the rear barrels? If the rear barrels are cracked open too far, that will act like a air leak and throw the front adjustments off. I have found sometimes if you go by Holley's adjustment procedure for the rear stop adjustment, they can be a little too far open and cause a high idle and idle quality problems.

 

WELL, Dave, I really appreciate your help on this, and since you are the only one with reliable advice, or any advice at all thus far, you sir are the man! What I meant by by holley carb settings, I meant the vacuum setting. I attached a vacuum gauge to the diagnostic port on the bottom and measured up to 16-18 inches of vacuum at idle. They advise to set the metering block to the highest vacuum at idle. With that being said, I have not messed with any of the stop screws at all (since the truck ran semi fine before minus the vacuum leak from the rubber cap on the diagnostic port) Anyways I am contemplating pulling the carb and checking out everything again. Any tips you are willing to give would be awesome. I will say that there were 2 gaskets included in the kit to seal around the intake manifold which is a edlebrock, and none of them really seemed worth while. I am not sure if I am able to post pictures yet, but if I can find a way, I would be willing to add them, or try to send them to you in a PM. If I am sucking air though, would the intake manifold gasket that seals between the intake manifold and carburetor be the only place sucking excess air? And yes the float level is set to your standards too. While the truck is running, and you remove the screw in the sight hole, it does not come out, but when you shake the truck slightly it does give a little dribble out of both sight holes. So that is correct, next is finding out why it wont idle, and why it wants to drag when you need to go forward, and have to give as much throttle as I do while disengaging the clutch. How about the power valve? Does that seem correct? since I am pulling anywhere between 16-18 inches of vacuum at idle, and my power valve is 6.5 for a manual transmission? (it is what came with the rebuild kit) Again, thanks for being my hero on this project Mr. Dave!

 

THIS IMAGE IS THE GASKET I STOLE OFF OF ANOTHER KIT THAT SEEMED TO FIT THE BEST AND INSTALLED.


THIS IS THE BOTTOM OF THE BASE PLATE


THIS IS THE TOP OF THE INTAKE MANIFOLD


THIS IS THE OTHER OPTION IN MY KIT


THIS IS THE KIT I AM GOING WITH RIGHT NOW AFTER I PULLED THE CARB THE SECOND TIME


HERE IS WHAT THE TWO METERING BLOCK GASKETS LOOK LIKE. THE ONE THAT I HAVE ON THE METERING BLOCK IS THE ONE I AM GOING FOR BECAUSE THERE IS AN ORIFICE BEHIND THE GASKET.

Anyone who has some insight for what I am doing right or wrong would be amazing, my grandfather wants his truck running, and it has already been down 3 weeks waiting on parts. Thanks!!!!!

 

OKAY!!!!!! so here is the update, installed the second version of the base plate gasket (different from the first) also adjusted the transfer slot position on the primary and secondary. Now it does not want to idle during warm up (no choke plate) and once it warms up it will idle, but only at 1200 rpm, even with the idle screw backed all the way out, so I shouldnt have messed with the secondary stop screw. STILL wants to act like it is chained to the ground when I shift to 1st gear to take off. Backing up is okay, only requires a little bit of throttle, but going forward, takes a lot of effort. anyone want to chime in? Mr. Dave? anyone?

 

Ok, so now it takes a long time to warm up, and doesn't run well till it does. Once it does warm up, it runs ok but it doesn't have the power like it should on take off.

I have a idea on the warm-up thing, but let's check the timing first. Do you have a vacuum advance dist with a vacuum line? Where did you hook the vacuum line? It should be on the port up high on the pass side front of the carb. At idle you should be able to pull this line off and it has no vacuum. What is the timing set at? And you should be able to take the dist vacuum line off the high port on the pass side, and hook it down low underneath on the pass side and the engine should speed up. Does it do this?

 

Well you are correct, the vacuum line is hooked up to the passenger side, and I will be completely honest, I have not tried that, but as of right now, the truck does not want to run at all. I have killed the battery trying to get the truck to stay running. I do not know what the timing is set to, and grandpa wants to say he knows everything and wants to rotate the distributor and listen by ear.... Dave, have you looked at the gaskets? Do you know which one I should be using? or does it matter as long as the whole base plate is sealed on the intake manifold? I feel like I should be paying you for helping me..... In the mean time, I will try the vacuum advance thing....

 

You can use either gasket. I usually use the one that is a little bit thicker if you have one that is.

 

Okay, well, I went and done that, I took the VacAdv off and plugged it. Then Hooked up the VacAdv to the diagnostic port on the bottom front of the carb. I got it running and it is idling fine now, it is pulling about 20 inches of mercury at idle, and when you floor it, it has power like you wouldnt believe without hesitation, once you start to give it some gas slowly, it wants to cut off until you get it past a certain point. I tested it with the VacAdv hooked up and off, and it runs the same. It didnt make any difference, no increase in engine speed or anything.... do you think the diaphragm in the VacAdv gone bad? would this cause my hesitation in acceleration or cruising? Took it for a test drive, and as long as you are accelerating it runs like a raped ape, if you want to just cruise, it wants to sputter really bad. I have no idea what could cause that. Idles great once it gets warmed up some (took the choke plate off) and when you wide open throttle, its like a hot rod.... but cruising speed it is terrible? Float level is correct too, while its running take both sight plugs out and gently shake the truck and just a little dash of gas comes out

 

Okay, well the one I have on now:

http://i614.photobucket.com/albums/t...ps7jhicxmu.jpg

This is the thickest one available, and the big opening is on the side with the EGR opening. So I am going to guess this is the best option even though my manifold has seam to separate the two banks:

http://i614.photobucket.com/albums/t...pshdssjaoi.jpg

anyways, it runs, it runs fast, and idles great, but much hesitation on take off. And there is nothing causing binding or grabbing now, I verified this by jacking the rear end up on jack stands, and manually spinning the wheels by hand with the transmission in neutral.