rod123

I have a 69 Torino with a stock 302 and a holley 600 that stumbles hard off idle. I just ordered on line a .035 squirter up from a .031 that it now has.

I need to also consider changing the orignial acc cam timing adjuster but I do not know which color to buy to help correct off idle stumble.

Any ideas ?

Thanks
Rodney Robbins

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Rod and Alica
63.5 Galaxie 3 pedals
69 Torino Convertible

PSIG

First things first - did it do this before? Is it a new carb? If you push down on the accelerator pump arm, does fuel squirt hard on both primaries - and for the full travel of the arm? Have you set the arm preload properly first? Was the carb adjusted for proper idle mix first? Usually a 'hard' stumble on anything reasonably stock to moderately modded is a malfunction rather than gross mis-adjustment.

David

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-=≡ If it was easy everyone would do it ≡=-

DeeCees66

I'm experiencing this same problem on my 351C. I have a 600 DP (4776-4) on it with a single plane Intake. I'm thinking I need to increase the squirter size as well. The rear squirter is larger than the front so I swapped them and it improved some. The primary was a .028 and the rear is a .032.

I got disgusted...so I borrowed an Edelbrock carb from a buddy just to make sure I had a carb problem.. Thing runs awesome with the Edelbrock, but I have to give it back at some point, and I'd really like to use my Holley if I can.

I watched a YouTube video, and they suggested to increase the Squirter 3 sizes at a time. And I do have it adjusted correctly as far as I can tell (according to what I've read/watched).

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66 Fairlane 500 XL (351C/Toploader)
49 Ford Club Coupe (8BA Flathead V-8)

PSIG

I know this seems redundant and a pain, but absolutely needs to be done right before making changes. First, be sure your ignition timing is correctly set (the primary word there is correctly). Anything done half-assed here will affect everything else as you go. Don't short-cut.

Then, follow a good basic setup guide, like this one. Be sure to read the link about vacuum gauges. When you've done that, read some other tips on basic adjustments here. Just gloss the whole thing a couple times to get the high-points and apply them.

Now - how does it run? Pretty dang good I'll bet. Where does it need more tuning? By this point the answers should be pretty obvious and fairly minor. Also, don't assume you need more when you need less or the same for a different period of time. For example, a stumble with a large-port and open manifold may not need more accelerator pump fuel flow, but rather the same flow over a longer period of time to let the engine 'catch-up' before the extra fuel is gone.

Enjoy the process, and post how it changes after following the basic tuning setup, and what you think it needs after that.

David

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-=≡ If it was easy everyone would do it ≡=-

rod123

WOW so very good tips.
My carb is about one year old and when it was a new carb it did not have this stumble. I let it set a little too long so I had to take the bowls off and clean them. I installed a new pump diaphram and cleaned the sqirter nozzles. The flow from the squirters seem fine but I am not a carb guy.

So i ordered the .035 squirter and will look at the setup directions you guys pointed to.

Thanks for the help, I am sure I will learn a little about Holley by asking questions and getting my hands deep into it.......

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Rod and Alica
63.5 Galaxie 3 pedals
69 Torino Convertible

dacofaII

Holley has a good book on it's carbs and it sounds like ACC pump timing off the ACC Cam. Make sure everything else is right first. and only change one thing at a time.

My427stang

Make sure the umbrella seal above the accelerator pump is good, if you didn't replace it, take it back apart and replace it now, then adjust the arm per Holley specs. It should move the second your linkage moves

Also, make sure the check ball, actually bullet shaped, is in place under your squirter.

If the car didnt stumble before the accel pump change, it should not require any change in design, it has to be something you did or you missed.

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70 Sportsroof, 427 FE/489 cid, TKO-600, 31 spline 4.10, A/C. modified Mass-flo EFI/CnC ported Victor.

Hottarod

Try the pink cams and 31 squirters front and back. Run the primary pump cam in the #2 hole and the linkage a little loose. Secondary pump cam in the #1 hole and linkage according to the book.

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1965 289 mustang fastback