Carb Problems - I'm About to Call a Pro

[palerider94]

Okay - bought a new Holley 600 put it on - took for test drive and car died. Could not get restarted right away - let it sit and and it started uo again. Did not seem like it was getting gas. Would want to fire from the accelerator jets but was not getting any gas from main jet.

Changed fuel lines (had original), fuel pump, sending unit, put filter at tank and carb. Same problem. Ran for awhile - little lean and the suddenly quit - I am getting gas in the lines - pulled line off carbed and checked. When turing over the car could not see any gas coming from the from main jets. Pulled float bowl off and not sprayed with carb cleaner - looked fine. I know it is not vapor locking - I have spacer on intake.

What should I try next? Appreciate any help..

 

[2nd Mustang]

Check float level in primary bowl? Make sure float actually floats?

 

[D.Hearne]

I suspect what you're calling the "main jets" are in actuality the venturis in the center of each throttle bore. You should not see fuel coming from them, if you do then something's wrong and it's running way too rich. You will see fuel squirted from the accellerator pump squirters as the throttle is operated. If you have a mechanical fuel pump, try removing the filter at the tank. These pumps are designed to pull fuel from the tank and sometimes a filter will prevent that from happening ( too much restriction). The floats should be initially set where they're parrallel to the bowl roof when inverted. When you reinstall the bowls, make sure to lube the rubber O rings that seal the transfer tube with brake fluid(or any other suitable lubricant for rubber), otherwise installing them dry will tear them and they'll leak.

 

[palerider94]

Went and got another carb put it on and the same problem. Tried running w/o fuel filters no difference. Checked to make sure choke was getting power (it's electric) that was okay. Is getting gas from the acclerator wants to fire but won't sustain it. Prior to problem was running okay - no indication of anything else. Called a guy that has done some work for me in the past and he said it was too old and not interested in working on it. So it look like I'll have to figure it - could use some more suggestions - Starting to think it is not fuel related. Here is what I've done so far:

1. Old carb needed rebuilt (ran but was flooding) - just bought a new one instead.

2. Changed all lines, fuel pump, sending unit in tank, drained gas and put new carb on. Blew out lines with compress air before hooking everything up.

3. Car started up was running a little lean got a little hesitation when I took it for test drive. But overall pretty good and then just died not sputter, backfire or anything. Did not start up right away but then restarted. No sign of flooding (no gas smell, white smoke, etc.)

4. Last night started up and again just suddenly died - getting gas from accelerator - sound like it wants to start but does not sustain.

5. Thought it was a bad carb - took back same problem - will not start at all - sounds like it wants to fire at least from gas shot in from accelerator. Don't think it is ignition since it does sound like it does fire. Also, removed filters and and gas is coming thru lines. Only thing I have not done is test gas pressure - thought it was okay since gas was coming out and new fule pump.


Again running out of things to check - would appreciate any advice.


thanks

 

[D.Hearne]

Wire the choke open. Give it 2 pump shots and crank it up. it should idle after warming up. If it doesn't you may need to adjust the timing to give it more initial advance. Adjust the throttle adjustment screw to where it's just moving the linkage, but no more. Adjust the mixture screws all the way in, then out 1-1/2 full turns. With the timing set at 12 degrees BTDC, it should idle on fireup. If it runs rough, look for vacuum leaks.

 

[palerider94]

thanks stupid question - You can tell I'm a little new at this - when you wire choke open - does that mean butterfly wide open or close? Going thru the Chilton diagnostics points to the choke. I'm just surprised I would have a problem with it since it is new. Appreciate your help.

 

[2nd Mustang]

Gas, air and spark. Looks like you're getting gas. Air is free, unless your air filter is really dirty and plugged up. Maybe spark, something like a loose connection at the coil.

Was it running prior to the carb change and why did you change the carb?

 

[D.Hearne]

thanks stupid question - You can tell I'm a little new at this - when you wire choke open - does that mean butterfly wide open or close? Going thru the Chilton diagnostics points to the choke. I'm just surprised I would have a problem with it since it is new. Appreciate your help.

Choke open= butteryfly wide open. Sounds to me like it's shutting closed after you start the engine, cutting off the air flow. I don't use em myself, no need for one here in south Louisiana. I take it completely off the carb. On cool mornings I just baby it till it'lll idle on it's own.

 

[palerider94]

Wide open no difference. Thought it could be spark pulled them plugs they were okay - put new coil on the old one looked original.

Put new carb on because the old rear float stuck and had gas spewing into bowl. Car ran great prior to this. When I put new carb on it ran for awhile enough to take for test drive - ran good just a little hestitation - idled fine. But it just suddenly died and will not start now.

Symptoms of not starting is pump gas once, turn key sounds like it gets a spark from the accelerator shot (right away) then that is it - almost like it is not getting any gas. Thought it was the new carb took it back and got another same problem. I know there is gas in carb because can see it coming form accelerator.

When rear floats stuck on old one gas was flooding carb pretty bad. I noticed it was even coming through gasket on the spacer that sits between manifold and carb. Could the flooding caused some problem - that may be cuasing the problem I am having now?

 

[dennis112]

Weird, it seems like you covered all the bases. I see that you replaced sending unit. How was the little filter on the end of the old one? Could you have crap in the tank that clogs it when the tank gets agitated?

I would be temped to take the fuel line loose on the car side of the fuel pump when the problem occurs and have someone crank the motor over to check for actual pressure. This is not safe, but could give you additional information as to the problem.

 

[2nd Mustang]

Another long shot: What is the condition of the battery? I once had a battery that died suddenly. I got a jump start from a tow truck and it would idle for about a minute then die. We jump started it again and same thing. No amount of gas pedal mashing kept it alive. It was the battery killing the charge from the alternator. There is a first time for everything.

 

[palerider94]

I pulled line off to carb and turned it over - plenty of gas coming thru - have not pressure tested it but appears to be sufficient. Battery is solid - cranks car no problem.

 

[zookeeper]

Given the fact you've tried to fix the carb several times, going so far as to replace the carb and that you're using the most reliable carb on the planet in my opinion, I'd bet it's not the carb. If I were you, I'd try to find a buddy with a good running car, then try your carb on his car to see if it works. Unless you messed with the idle mixture screws, float levels or something else, you should be able to simply take a new Holley out of the box and slap it on the car with no problems whatsoever. I've done it several times over the years and the last pair of Holleys I bought even had a tag attached saying pretty much the same thing, "don't touch anything, we test all all carbs" or something to that affect. Anyway, if you only pump the accel pedal once and expect the car to run nicely, that's the problem. Pump it AT least twice. My brother has a 600 Holley on the 406 Chevy in his Model A and it will not start unless you pump iit 8-10 times. The 650 Q-jet replacement in my wifes 427 Corvette also requires 8-10 pumps before it will fire. I know lots of experienced carb guys are wincing at the idea, but in both of the cars I mentioned, you can drain the battery before it will start other wise. At best it will (pay attention here) start momentarily, then die and be a bear to restart. Sound familiar? Carbed cars are not like EFI cars and they take a little finnesse and a ceratin technique to get fired on cold mornings.

 

[palerider94]

I just spoke to Holley hotline. They said a lot of times with the new carbs the float gets bang around in shipping and needs to be reset. There is not a float adjustment or site glass on new ones like the old ones. Basically preset and he said you need to bend the tang to get it right. After I described the probelm and symptom - he jumped on that solution right away. I also told him that this was the second carb and still having the same problem and he was not surprised. I'll take a look at it when I get home. That would explain a lot

Would be interested if anyone has instructions on setting floats for new carbs. Got verbal instructions from Holley Hotline - but written would be good.

 

[Pakrat]

Well, just to echo what Zoo and Hearne said, I can tell you for sure it's the same for my setup. I have the Holley 600 as well and even though it's a New England car I only drive it in the summer, so I took the choke off my car completely as it seemed to hinder my cold starts. Thru trial and error I learned that with 13-14* BTDC of timing and a soild one pump to the accelerator pedal followed by holding it at half pedal that it would crank over pretty much the first time every time. The first cold start of the season it may require an extra pump or two but that's it. It's also important to note that until it warms up I do have to flick the pedal a little some times to keep it from dying out. Definitly wait a good 30 seconds between failed starts too, you don't want to fry your starter. Did you ever say what your timing was set at? Also, what type of ignition are you running, electronic or points still? Maybe a poor gap isn't helping any?

 

[palerider94]

The 600 Holley I had replaced was the same way i push to floor and 1/2 up started pretty much the first time always - until the floats stuck and I decided to replace. I'm starting to think I should have rebuilt it instead of buying a new one. Still running points pulled cap (plan on replacing one day) off last nite contact points and rotor tip looked good. I'm not sure of my timing was running solid prior to this. I'm going to take a look at floats tonight as suggested by Holley hotline. If that is not it I got a friend of friend who is a pretty good mechanic coming over this weekend (at a price) to help out. I'm just impatient and it kind of feels like giving up when I got to call a mechanic over to help. Thanks for tips - I'll post how thing work out.

 

[krash kendall]

My take on this you have a poor seal between two of the four mating surfaces of your intake, spacer, carb base setup resulting in a large vacuum leak. You say at one point when you flooded it you saw fuel apparently leaking out of it.

Here's what may be happening:

-You start the car cold and the choke comes on compensating for the vacuum leak and allowing the car to run.

-When the car warms up and the choke goes to the open position, the vacuum leak causes a lean situation and the vacuum advance is also affected.

-the car dies and is a pain in the a$$ to restart untill it is cold enough for the choke to engage again or you pump enough fuel into it on repeated attempts.

That's a simple thing to test for. You may be able to ditch the spacer and put a new gasket under the carb to solve the problem.

 

[D.Hearne]

My take on this you have a poor seal between two of the four mating surfaces of your intake, spacer, carb base setup resulting in a large vacuum leak. You say at one point when you flooded it you saw fuel apparently leaking out of it.

Here's what may be happening:

-You start the car cold and the choke comes on compensating for the vacuum leak and allowing the car to run.

-When the car warms up and the choke goes to the open position, the vacuum leak causes a lean situation and the vacuum advance is also affected.

-the car dies and is a pain in the a$$ to restart untill it is cold enough for the choke to engage again or you pump enough fuel into it on repeated attempts.

That's a simple thing to test for. You may be able to ditch the spacer and put a new gasket under the carb to solve the problem.

Sounds plausible to me. I also agree about the spacer, if you've got an aftermarket intake and a factory PCV spacer, that's just about a guaranteed vacuum leak. The spacer overhangs the thin carb base on the intake and you've just got a gasket there covering the open bottom spacer.Another thing--- Ditch the points for a Pertronix unit.(you'll wonder afterward why you waited so long to do this) Points SUCK, BIG time. The Ignitor I will cost you about $60, add the Flamethrower coil. Install a new cap, rotor, wires if your's are old. Pull the plugs and clean em, fouled plugs don't work well and with a weak spark, won't fire reliably. Sounds also to me like you've got a model 4010 Holley there, no the usual list 1850 carb. I've never messed with these, but they look similar to an Autolite 4100.

 

[palerider94]

Well I tried the adjusting carb as Holley described - got a little excited when I pulled off float bowls and seen they were not parrallel like hot line siad they should be. Adjusted and in any case no go. Car is not starting for nothing now. Sound like it wants to fire then nothing. From what I understand new Holley starting later last year no longer have adjustable floats. Almost feel like adjusting to it floods out and see what happens. I liked the older style with site glass - then you knew for sure.

In any case I will put a new spacer on - need one way. Have an intake oil leak in back was planning on taking intake off and having bead blasted as my next project.

Will buy the Petronix - What about the Petronix II? Also, they have 3 listed - not sure which one I need

1. 8 cyinder single points
2. 8 Cylinder dual point w/o vaccuum advance
3. 8 cylinder dual point w/vac advance.

I have 2 vaccum hoses going from carb to to distributor. Been a long time since I messed with points - what ae the symptoms when they go out?

Thanks again for the help.

 

[zookeeper]

Your distributer is a single point, vacuum advance. The reason you have two vacuum lines is that your vacuum advance canister is one of the dual diaphram units and you likely have a temp-control vaccum port on the intake at the other end of the vacuum lines. I suggest swapping it for a single diaphram unit for simplicity sake, then remove the temp-control vacuum unit from the intake, then plug it with a pipe plug and use the vacuum port on the metering block of your Holley for the distributer.