Primary Accel squirter nozzle

[Henry Cloutier]

Greeting you all,

Can you provide me the part number squirter nozzle assy. part number for the 4053? I'm assuming what is installed is the stock .025 (although when I rebuilt the carb I could find no identifying marks) The engine now that it's getting colder outside has a hesitation just when the throttle is applied. The stumble is momentary, and the engine responds fine after. What I've read is to go up two sizes but there are so many different styles to choose from I'd like to be sure before placing the order.

Thanks, and Happy Holidays!

Hank
   

[Stingr69]

The nozzle is stamped with the number on the side.  .025 shooter was stock. 

You might also want to play with the pump cam.  The quicker acting (red/pink?) pump cam worked well for me with a .025 shooter.

How did you set the primary throttle blade screw setting?  A lean tip-in can come from having too much of the transition slot exposed at idle.

How many turns out from lightly seated on the mixture screws? 

Do you get a lot of fumes smell?

[Henry Cloutier]

To be honest I set the idle according to rpm and adjusted the mixture screws as needed to achieve the best idle. This was performed following the carb reseal and before I understood the significance of the secondary blade adjustment screw. I do remember noticing the secondary blades were slightly cracked open and I didn't change that. I didn't think about a cam change...
I don't have any fumes after driving and parking in the garage, that's the reason the carb was pulled to begin with; the garage would stink of fuel for a few days after driving before.

Thanks and best regards,
 
Hank
   

[Stingr69]

The transition slot opening can be closed up using the RPM screw so the slot looks like a square when looking at it from the bottom of the carb.  If yours is exposed too far it may look more like a rectangle. It does not pull as much gas at tip in if it is too far exposed. You can get the bog that way.

[Henry Cloutier]

I do believe I did look at that when the carb was off and noted the transition slots were close to or square. Since then most every idle speed adjustment has been to adjust for lower rpm. I'm going to try to look down from the top today (not sure this is possible) and try to see how much slot is exposed. Maybe I can then make a comparison to the photos in the Holley book.
I also remembered last night the spring on the accel pump linkage was partially collapsed thus requiring a washer to take up the play. If the spring is weak perhaps that is contributing to the bog.

Thanks for your help on this!

Hank     

[Stingr69]

The accelerator pump linkage must not have any slack and it must not bottom out at wide open throttle.  Any slack at all will result in a bog.

If the adjustment is too tight, you may end up with slack when the linkage bottoms out after a wide open throttle stab...assuming the linkage bends and nothing breaks.  Not sure where you would add a washer?

If the RPM is too high, you might have a vacuum leak?  Secondary butterfly stop screw setting?

What does your distributor curve look like?  Timing setting?

[Henry Cloutier]

Basically, the spring is compressed and trying to adjust the WOT pump arm clearance of .015 wasn't possible as the tension went away as the adjuster bolt was lengthened. The spring is shorter now than when it was produced. I put a washer between the spring and the pivot arm on the bolt to take up the clearance so I could get the car started after the rebuild/reseal. I guess I figured if it worked fine but it's completely possible the geometry and or tension is far enough off to be affecting the amount of fuel being pumped right off idle. I'm ordering a new arm/spring assy from Holley to replace the assy on the carb now.
RPM is 900 on the tack and about 850 on the timing light.
I do know the secondary butterflies are cracked open slightly and I didn't change the stop screw during the reseal process so not sure how much of a turn from closed the screw actually is.
The distributor is still factory plumbed to ported vacuum, initial at 10 degrees, 36 degrees at approx 3400 rpm, increasing from there as rpm increases. The engine pulls clean and hard, it's just that right off idle hesitation I'd really like to get rid of.
Having rethought about trying to see the slots from the top is just silliness. The only way to really get there would be by borescope and even then it would be a wild ass guess.
 

[Stingr69]

The finger that rides on the colored pump cam may be bent.  You should not need a washer at that location.


The linkage arm at the front (first picture) will have zero slack at the bottom where it touches the diaphram pump lever with the throttle at rest.  Adjust the spring bolt setting so that it just slightly compresses the diaphram lever under it. 


You need to have .015" ADDITIONAL TRAVEL AVAILABLE at wide open throttle. This means after you are done adjusting that spring bolt to "slightly tighter than zero"....you should be able to go WOT and not bottom out the diaphram.


If you went too tight on this setting before, you probably bent up the finger (second picture) that rides on the colored pump cam.  Might need to bend the finger back down to correct it if the spring adjustment at the front the is not long enough to reach the diaphram lever anymore.


If you change the RPM screw setting, you should recheck the spring bolt setting every time. 


If you get a bog, you probably have slack in the spring bolt setting.

[Henry Cloutier]

Yes, I agree no washer should be needed. However, when trying to adjust for the .015 clearance the spring lost contact and was no longer loading the pump assy. I put the washer in to be able to adjust for the .015 and keep the bolt loaded. It's entirely possible the arm is bent and as stated a new assy is coming. This carb was a real mess when the car arrived basically leaking internally and externally. I'm finally down to this!
Not sure when the new arm assy is arriving but I'll report back once installed.

Thanks for all your help!

Hank

[Stingr69]

I would bend the finger down with pliers.  No biggie.

[Henry Cloutier]

Hi all,

Received the accel pump arm/spring assy from Holley this weekend. Compared the original arm to the new one and didn't see any difference. So I removed the spring/bolt components and installed on the existing arm. The engine responds much better now with much better response to inputs given as related to previous configuration. Thanks to Stingr69 for assisting!

best regards,

Hank