Holley Carb help

[bronconate68]

I'm ready to give up on this Holley. So the float bowls were over flowing. I adjusted the float levels until the fuel was just below the site window (which didn't have clear plugs). The motor was idling perfect. The air fuel mixture was good. The motor was up to temp before I started adjustments. As I was preparing to take it out for a test drive. Ten minutes or more of idling while I squared stuff away. Then it stalls. It cranks and cranks. I open the throttle all the way and it starts, runs for 30 seconds then stumbles out and dies. I check the float fuel level and they are empty. I make adjustments to raise the floats but the bowls never fill. What kind of crap is that!! I'm calling Holley, if they can't help me I'm bailing for an Edelbrock.

 

[baddad457]

Pull the needle/seats out and either clean them or replace them. You can buy new units at most any parts house. Sounds like yours got trash in them. I'd also pull the "rock" filter behind the fuel inlet nipples out and inspect them for trash as well. What carb did you have ?

 

[SHX669]

When adjusting the floats you have to "use" some of the fuel from the bowl . When you lower the float that displaces fuel - temporarily RAISING the fuel level . But then as you use fuel the float and fuel level will drop - there are multiple instructional videos on this.
That being said ; the bowls should fill back up relatively quick - unless you have the float/seats adjusted extremely low and unless there is a fuel delivery problem somewhere in the system.
SHx

 

[bronconate68]

Thanks guys. No fuel delivery problem. I have the Off-road truck avenger 770 cfm. I spoke to Holley, of course they really didn't want to listen, it was all about where or whom I purchased it from. I had to ask them to at least give me some troubleshooting for the specific issue. Not much help but a little. I'm going to pull the bowl and look at the float. If I have to purchase anything new to make this work then I'm going to bite the bullet and purchase an Edelbrock. At least I know my way around those. The strange thing is that I had the Holley working great. It was doing everything prefect until it stumbled out and died :-[. More to do...

 

[baddad457]

If you're going to pull the bowls, invert them and adjust the float so that it's level. That should be all the adjustment needed. I can't recall the last time I had to make any other adjustment to the float level after doing them this way. When you go to replace the needle/seat or reassemble the single feed bowls, dip the rubber O rings in brake fluid before assembly to lubricate them so they don't tear as they're inserted into the metal parts.

 

[bronconate68]

If you're going to pull the bowls, invert them and adjust the float so that it's level. That should be all the adjustment needed. I can't recall the last time I had to make any other adjustment to the float level after doing them this way. When you go to replace the needle/seat or reassemble the single feed bowls, dip the rubber O rings in brake fluid before assembly to lubricate them so they don't tear as they're inserted into the metal parts.

Great! Thank you for the advice. Inverting the bowls is what Holley suggested to make the proper float adjustment. There are two bowls, are the both used in tandem or is one bowl (the one in back closest to the cab) just for the secondaries? I'm still not clear on how they are utilized even after reading the Holley instructions.

Thanks again for all your help with this issue.

 

[pcf_mark]

The bowls are unique front to rear so keep track of them if you take them off. In your case it may be impossible to mix them on that model. These carbs are simple and will run forever with clean fuel. Can you look down into the carb when it stalls / dies? Will it start back up? If you try to re-start do you need to floor it and hold you foot down to clear it to get it to start? Then do you get a cloud out the tail pipe? If it is flooding you will have fuel dripping out of the boosters (round things in the center of each throttle bore) when it is flooding.

If you have trash getting in the needle and seat a switch to an Edelbrock will not prevent this.

Take a look at this link http://www.vintagemusclecarparts.com/pages/needleandseat1.html

 

[bronconut73]

The Edelbrock sucks off road Bro.
The Holley is uber adjustable.
I found a guy at Holley Tech. named Kyle XX. He not only helped me immensely but swapped out an old defective Holley 770 TA for a brand new one. He made it simple, he made it easy, he made me a Holley guy for life.
Ask for him at Holley Tech.
His name is Kyle XX.

 

[bronconate68]

Take a look at this link http://www.vintagemusclecarparts.com/pages/needleandseat1.html

Thanks for the link. Currently the carb is running out of fuel. If I wait 5 min and start the motor it will fire up and run for 30 seconds or so then stumble and die. If I don't wait the 5 I can put the throttle to the floor and it will start. I didn't get a chance to pull the carb tonight. The fuel system is clean and I never had an issue before running with an Edelbrock on my last motor. I did have the Holley running sweet for about 15 min before it ran dry. I could get on the throttle hard and the response was excellent. The motor sounded great and I was even able to set the air fuel mixture. I'm hoping I can get this carb running proper. I would hate to have to lay down another 4 bills for yet another carb. So I am motivated to work with the Holley.

 

[baddad457]

You can't mix up the bowls on a Holley: one front, one back. Front is the primary, rear is the secondary.

 

[bronconate68]

To follow up; I finally got to this today. I pulled the bulls and the floats were pinned at the bottom of their bowls. I made the adjustments and the fuel level is just below the site holes. When I fired it up I noticed I have a exhaust leak at the passenger side header. During the test drive it started out fine, a mile down the road at the first stop it sputtered and backfired out the exhaust. I leaned out the mixture about a quarter turn and still have a some sputtering out the exhaust when coming off the line.

I need to fix the header leak before anymore adjusting of the carb. This new motor doesn't tolerate the loss of vacuum at all. I noticed that first thing at the first firing of this motor.

Other than that it was touring around just fine. The transmission kicks like a mule when it shifts under a little extra throttle;D

Thanks again for all the advise on this issue! You guys rock!!

Nate
'68

 

[broncnaz]

Exhuast leaks dont affect vacuum.
With the floats pinned to the bottom of the bowls most likely the needle seats are bad. they were probably screwed all the way in to try and prevent flooding. I'd get new needle seats. Id suggest the regular ones over the spring loaded ones as I've always had issues with them.

 

[bronconate68]

Shows what I don't know. A set of needle seats on the way. Thanks

 

[inthmtns]

These may sound completely from left field but without actually working on the vehicle, they are some ideas...

Is your PCV (Positive Crankcase Ventilation) working correctly? If it is plugged, leaking or non-existant it will have dramatic impact on your carb tuning. You should have a minimum 5/16-3/8 line from engine vacuum to one of your valve covers. (Lack of a PCV system will generally require leaner jetting)

Next... I fixed a 1977 F150 that had the same issues as yours, idled fine but ran out of fuel after a short distance. It turned out that the new fuel tank cap he used did not have a vent in it.
Each time he tried to drive it the fuel pump pulled fuel until their was enough vacuum in the tank to stop the fuel flow. When you unscrewed the fuel cap air would audibly rush in.

If you have dual tanks, is your switch gear in good shape? Could it be sucking air at one of the fittings or through and old valve?

I have also seen on older Ford's where the 'sock' on the pickup tube in the tank became clogged with rust/scale and debris causing fuel delivery issues similar to carb problems... this requires fuel tank removal and cleaning, though you can 'blow' the sock off of the tube with compressed air to diagnose.

No guarantees these are related to your issue, but all have caused symptoms like you described.

 

[bronconate68]

OK, I fixed the header leak and took my Bronco to the gas station, about a four mile round trip. The motor ran great. There was some backfiring out the exhaust only when it shifts into second from first. I can power out of it but have to watch my speed. It also wasn't consistent. On the way back from the gas station it seemed to not backfire as much and sometimes not at all (A few stop signs and lights). The backfiring is a light popping with the power stuttering to match. I did not replace any needle seats. Once the popping stops I can give it gas and climb to the next shift point without any issues. Only backfires (crossfires?) after the shift from 1st to 2nd at normal to slow speeds. If I'm aggressive with the throttle I get a little, if any, of the backfiring after the shift.

I'm going to take the Bronco off road on Friday. I will post video which I hope will document the issue. I wish I knew a good Holley guy. I'm sure it just needs a knowledgeable touch.

 

[broncnaz]

Carbs are easier to work on than you think. I would suggest getting a rebuild kit for your carb especailly if going offroad at least to have just in case. Most carb kits come with instructions which may help you pinpoint/fix your issue a little better.
Seriously if you learn to work on the carb yourself you'll be suprised at how easy it is and you probably wont have another problem you cant fix easily.

 

[bronconate68]

Carbs are easier to work on than you think. I would suggest getting a rebuild kit for your carb especailly if going offroad at least to have just in case. Most carb kits come with instructions which may help you pinpoint/fix your issue a little better.
Seriously if you learn to work on the carb yourself you'll be suprised at how easy it is and you probably wont have another problem you cant fix easily.

Yeah, I'm working towards that with this Holley. I pretty much figured out Edelbrocks, could work them real good. This Holley is a bet more complicated, but I have been able to get it to work so far. I purchased it off of ebay as a refurbished item from the Holley store. Don't know yet if that was a good idea or not.

I think I'll follow your advise and pick up a rebuild kit to have on hand. I found one on-line for ~$28 so it is a minimal cost for some security. I'm hoping this carb isn't to big for my motor. The oil doesn't smell like gas yet so that's a good sign I guess. The gas mileage is pretty low though. I'll collect those numbers on Friday.

 

[broncnaz]

Well its all the same tuning concepts. Personally I like tuning holley's better than edlebrocks. 770 cfm should be fine on a 408. You could go smaller if you dont plan on running above 6000 RPM. A 670 might give a little better driveablity.

 

[bronconate68]

Ok, here is a video from yesterday;

http://www.youtube.com/watch?v=Cwl3g-lZdL8

at 3:40 coming off of a stop sign it stumbles. This is a rich stumble that becomes more constant as the motor gets closer to running temp. It is an initial squirt that is flooding and causing the stumble. I can be running down the road at 50 mph take my foot off wait for it then give it gas and get the stumble. There has to be an easy adjustment for this.

Other then that I was happy with the way it ran.

Thanks.

 

[broncnaz]

Id pull the plugs see what they look like.Overall jetting may be off which can contribute to the isseu. Kinda hard to tell from the video but it appears to take off from a stop ok just as the revs come up it stumbles? Im wondering aside from the jetting if the seocndaries are opening to soon.