Holley issues

[Bextreme04]

Update, I drove the truck around the yard a little today it fires right up idles fine doesn’t like taking off(accelerator pump?) and it seems to flood out in lower rpm times like I was backing up to the shed and it flooded out and stalled it started back up but stumbled and was smoking I put it in drive took off and it cleared up and ran fine. Could idle mix be the issue with the low rpm flooding? You can tell when it’s starting the issue because it acts like it’s got a cam with huge valve overlap and the accelerator pump issue worsens.

That's exactly what I just finished messing with this weekend on my 67 Buick Riviera. That's a 4150 Holley. 650cfm vacuum secondary with an electric choke. Set your float height like others have said. Just search 4150 holley float height adjustment and you'll find a nice video on youtube form holley explaining exactly how to set it. Then do the same with the idle mixture screws. Then do the same with idle and high idle set screw setting. I would probably do all of that after getting a rebuild kit and rebuilding the carb. They are easy to rebuild.

 

[Ricko1966]

A link that tells you how to check the power valve

Carburetor Valve Problems - Tech Article - Chevy High Performance Magazine

Read the tech article on Carburetor Valve Problems, brought to you by the experts at Chevy High Performance Magazine

www-motortrend-com.cdn.ampproject.org

Holley has a page telling you how to pick and fine tune the power valve.

 

[potent rodent]

first off did u check and adj your float level, as said abouve u need to do this first off, on your acc pump look and see if gas comes out of the squirters as soon as u give it gas , look and see if your idle air bleeds are not pluged up run a fine piece of wire down them,from the looks of the carb it could use a good rebuild is your big block stock ?

 

[potent rodent]

That's exactly what I just finished messing with this weekend on my 67 Buick Riviera. That's a 4150 Holley. 650cfm vacuum secondary with an electric choke. Set your float height like others have said. Just search 4150 holley float height adjustment and you'll find a nice video on youtube form holley explaining exactly how to set it. Then do the same with the idle mixture screws. Then do the same with idle and high idle set screw setting. I would probably do all of that after getting a rebuild kit and rebuilding the carb. They are easy to rebuild.

thats an 1850 600 cfm

 

[potent rodent]

also also set your air fuel mixture screws to around 1.5 turns out , when adj them screw in and back out to get the highest rpm then go to the other side and do the same thing

 

[Ricko1966]

And the most important thing is ignore everyone's suggestion to check float level and second I sure wouldn't check the power valve if it was me. I'd just keep adjusting mixture and updating us on how it doesn't run right.

 

[potent rodent]

u r right abought the pv if its blown or the gasket is torn every holley iv had runs rich, i go into the ifr and lower it and make sure the trans slots are no more than around 0.30 thou

 

[iamtherealJayy]

Alright alright, I’ve got updates. I’ve actually done half of what’s mentioned. I checked the floats they’re too high but the flathead screw nut combo was stuck together and I ripped the gasket so that leaks now. The accelerator pump does not pump the arm doesn’t press it down the spring just compresses. The idle mix screws are currently 3/4 of a turn out because I ran both of them in and it never idled down. I noticed the passenger side secondaries Venturi drips fuel.

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Is this something a rebuild will resolve? I had a white haze before turning the idle mix screws in that went away after turning them in. With full manifold vacuum being at around 19/20 at idle the engine doesn’t run bad but no accelerator pump makes it so you can’t really get on the throttle and if you do it floods(fuel building up on secondaries and dumping when they open?) also @potent rodent ita a sbc not a big block lol. It’s got a th400 trans and when I was under it I noticed a spade connector type deal right by the speedometer cable (I was installing a speeedo cable it was missing) any ideas what that is? I believe the truck was originally a 4 speed truck later converted to an automatic. I’m not super familiar with automatics but I think this one is missing a few pieces. Isn’t there supposed to be a kickdown cable at the throttle linkage? The only thing I’ve seen connected between carb and trans is a vacuum line from the back of the carb to the trans near the cooler lines. I’ve already ordered a rebuild kit it just hasn’t arrived yet. This is my first holley rebuild lol.

 

[Ricko1966]

On top of the other issues.If you can screw the idle mixture screws in and it still idles you probably have a bad power valve,that is assuming you dont have the throttle stop screw ceanked in so that you are idling on the transition circuit..

 

[iamtherealJayy]

So power valve is also an issue, that’s fine I’m completely cleaning and replacing everything in the carb. I think someone on here mentioned a backfire will destroy the power valve? Is that true? I haven’t touched the timing yet because I didn’t want to cause a backfire and destroy it if it wasn’t already bad.

 

[Ricko1966]

So power valve is also an issue, that’s fine I’m completely cleaning and replacing everything in the carb. I think someone on here mentioned a backfire will destroy the power valve? Is that true? I haven’t touched the timing yet because I didn’t want to cause a backfire and destroy it if it wasn’t already bad.

Read the link I put up for you,some holleys a backfire is almost a quranteed destroyed power valve,some NBD, and there's an update that can be installed to prevent this. Only you can determine what you have.If you are rebuilding,now is the time to pick the correct powervalve for your engine.

 

[iamtherealJayy]

I’ve read the article but I don’t understand about picking which one i need? It’s a stock 350 as far as I know with a th400 trans. I identified that spade connector with no wire as the electric kickdown, my apologies. I plan on either selling this truck or making it a tow rig of sorts. I’m constantly buying, selling, trading vehicles so I need a way to move them around. I now know my work truck won’t do it with the 3.08’s it barely has enough torque to pull itself around.

 

[Ricko1966]

Yes Perry, I seen the thread and was sorely tempted but refrained because once again this seems to be a case of someone who may be use to a piece of S=HIT Q-Jet instead of a good carb like the HOLLEY which they currently have. Once the OP gets used to having a REAL carb as he does now, he'll be spending more time driving it and less time f=ucking with it.

Well so much for that thoery.

 

[iamtherealJayy]

I’m actually not “used” to any carb in particular. I’ve got one quadrajet truck and it’s only been on the road once. The trailer ride home. I daily an edelbrock truck but I didn’t choose edelbrock the carb was given to me. And I drive a throttle body injection 87 frequently. Every one of them has their own issues in their own ways lol

 

[Ricko1966]

A link that tells you how to check the power valve

Carburetor Valve Problems - Tech Article - Chevy High Performance Magazine

Read the tech article on Carburetor Valve Problems, brought to you by the experts at Chevy High Performance Magazine

www-motortrend-com.cdn.ampproject.org

Holley has a page telling you how to pick and fine tune the power valve.

Here.it is.

How To Tune The Power Valve In A Holley Carburetor

How to ensure your Holley carburetor is using the right power valve for your engine. Holley carburetors have a power enrichment system that provides fuel to the main power circuit during heavy loads or under full throttle situations. The vacuum operated power enrichment system is controlled by a...

www.holley.com