Tony:  I have watched dozens of carb videos, this is great stuff.   As an 81 yo retired surgeon and car guy,  I apprieciate your wonderful teaching skill.  Love the detail.....have not been having  many carb issues on my 37 street rod, but it makes me want to pull the Holley off and go through it just for the fun of the educational experience.  THANK YOU!!!! So impressed!!

I know Uncle Tony isn't going to change his ways now but as a tip for the newbies out there, I recommend  spreading out an old towel on the table when opening up any carb. I've been doing it on a towel for many years and it really helps to maintain control of flying BB's and springs.

I actually like the 4150 double pumper mechanical secondary carbs. Modular, easy to understand, very tunable and easy to tune .

This is what I really like about UTG. He's really good about covering things nobody else does. And I can always go back and see what he did when I'm troubleshooting.

The best advertisement for Carter Carburetors I’ve ever seen, nice!

I've had carbs on my stoopid hot rods since 1989 but I'm not a Holley guy. Thanks Tony!

I can remember how mystifying a Holley was to 15 year old me. I bought a book specifically for Holley four barrels and practically memorized it. Could rebuild my 4779 double pumper with my eyes closed.
Watching this video was like visiting an old friend.

And this is why Edelbrock will always be my go too.  Thanks Tony👍

Excellent tutorial. Rebuilding carbs is one of the basics when working on old cars, but I always feel like there is more to learn.

@uncletony , you didn't mention the optional " 50cc Accelerator Pump " available on many double-pumpers . the pump diaphragm , pump housing , pump spring . pump arm and pump cam are all different from the standard pump system .
older 4160 side-line single-pumpers can benefit from a  " 50cc Accelerator Pump " conversion . though only recommended for standard transmissions .

This video is great. You just covered in a short amount of time, what it took me over 6 years of carb tuning/rebuilding to learn.

I am well versed in carbs but I still learned something new.   this video is a gold mine!!!!!

UT.   Holley 4 barrel primary tuning.  Wide band air fuel gauge zip tied to the bottom of a carpet scrap.  A lighter plug to power the gauge.  
In neutral bring rpms to 1,700 rpms. Is your air fuel ratio at 14.7.      Then bring rpms to 3800 is air fuel ratio at 14.7.  
At 1,700 change idle feed restrictions to get to 14.7.
At 3,800  change primary main jets to get to 14.7.  These are unloaded.
With both changes made. Crack primary throttle hard.  If it pops in the intake go up a size on the primary pump nozzle.   The off idle flat spot is gone.   Holley and edelbrock took this how to turn the low speed circuit out of manuals.  So professional carb tuners had something to work with.

Great video!  I've been using Holley carbs for 50 plus years.  They certainly aren't perfect but I know how to work on them.  I can tell you the blue gaskets are the way to go.  With the old cork style if the car sits for like a year the carb is going to leak!  When all the internal passages are clean and work, the accelerator pump is good, the float bowl gaskets aren't leaking and the float needle and seat are working Holley's are great carbs!

With every video, I learn something new. Awesome stuff!

Tony. Thanks for the rundown.    Its true that a little stumper can jog youre mind enough to get into a flippin disentary type of presentation taking the subject from top to bottom completley.

One of your best videos you have done!

Every accelerator pump I've dealt with was warped and leaking. Sandpaper on a flat surface fixed it every time. Then Edelbrock.

HOWdy  U-T-G, ...
WOWSER = decades of  HOLLEY  Double-Pumpers & never had these Problems
Thanks
COOP
...

This was way above a newbies or a fuelinjection person but a very good video for people that tune and know holleys.