Hey Bob,

Yeah mine could just be a cheap knock off or the coil spring could be flipped, who know......Choke Works Perfectly fine, its just the
- Dip in Hesitation during low RPM
and
-Exhaust Fumes at Idle

BB2 pointed out something about choke orientation.  The one in your picture is way off.  I bet the end of the choke heater element is not correctly attached to the internal linkage. Remove and reinstall properly.

Part throttle acceleration is more controlled by the power valve than anything. Try a higher number.

I do not understand Holley carbs being called a racket.  Are they supposed to build an exact carb for every  unique engine that is out there?   You have to tune any carb to work on your particular car.  Some carbs may come out of the box with richer jetting, or whatever, that better masks their inability to be perfect, but all need some tuning unless you just happen to get lucky.

The choice of a double pumper carb on a street-only car is probably not optimal.

Fix your choke. It is incorrectly installed. Note if no HOLLEY name on it, it might be one with a reverse wound spring.  It can only work better, if you check it out and be sure it is hooked up properly inside.  Put a richer power valve in it. It will run better.  Retard your timing a couple of degrees. It will stink less. You will get there.  All you have to do is pull the bowl to make changes, not the entire carb.   It is a pain. I hate it, as well.  But the satisfaction of getting it right will make up for it.

Resonding to "As of Now I made an Adapter to Steal 12v from my Reverse Lights and I put an Inline 10AMP fuse, is that a good number or should It be Higher than 10??? "

I have a 4 amp fuse for my electric choke and Tach, no issues.  I coupled the choke and tach together so if the tach stopped working, I'd know to check the choke.
 

Last edited by BobE (4/27/2020 8:19 AM)

A higher number on the power valve will make the transition circuit richer. = more gas.

Do not change more than one part at a time.

Even the Holley web site sells Quick Fuel brand power valves on their web site at a price around $7.  The Holley valves are $17 or so. Either work fine.   On my 427, I installed a 10.5 valve to see if my mid-range stumble would go away. It did.  Now to try smaller valves to see how much leaner it can be and still run right.  PITA, you bet, but it sure feels great to be running great. Stock valve was 6.5, so not that many options to try.

I only went to 10.5, knowing it would be way rich, as a test to see if anything was going to change with a richer power valve. Since it did change for the better, now it is just a matter of dialing it in with the leanest power valve that will make it run correctly. Luckily I have a full time AFR gauge in the glove box.  It is telling me I am running rich.  Without the gauge, the assumption would be it is running fine... so leave it alone.  But better mileage can be obtained by fine tuning.

M1Mustang69 wrote:

I gotchya MS.....

Ok here's the update.....Luckily I had a 8.5PV just kicking around....so changed that from a 6.5....Started the car, she warmed up enough so I could take it out....drove 5min before hitting the highway with traffic lights, gauges said it was to temp but that little Hesitation/Kickdown sensation was present the entire way (did notice different RPM ranges for different gears....which I thought was weird but maybe you can make sense of that?)...1.st gear Id say non existant, 2nd gear most consistent yet gone at 3500-4000rpm, 3rd gear 3000 and under, 4th same as 3rd

drove on the highway in 4th between 50-60mph for 2-3min and it continued to have that hesitation....GET THIS, after this length of driving, it started to go away.......all the way home, all the gears it was gone.......

One Other IMPORTANT factor, or at least Im pretty sure its important.....So the car sat for a day without running before I attempted this.....when I cracked the front bowel, barely any FUEL came out....im talking a table spoons worth......

Is that Boiling Over or a residual pressure/Check valve somewhere in the system has failed?

MS wrote:

Check the accelerator pump diaphragm.  It could be leaking and also causing the hesitation.  Use a GREEN one, since they are designed for fuel with alcohol in it.


Symptoms of leaking accelerator pump diaphragm:

Hard to start due to fuel leaking out overnight.  Might not see fuel leak as it can evaporate when it hits the intake manifold.

Stumble on acceleration.

Poor gas mileage due to leak while driving

Both Accel Pumps changed couple weeks back....Oddly enough the primary must have been leaking since I started driving it, less than a week after I replaced the primary the secondary was leaking.....
coincidentally I used Green

I have been monitoring the Pumps closely for over a week, no leaks........

Did you ever 'share-with-us' info about your ignition timing.....ignition curve....total advance...etc.?
  Many times a "hesitation" can be cleared up with timing tuning.  Engines with "a bit of a cam" need a good timing curve to ever run right.
Jus say'in!
6sally6

red351 wrote:

Not to say that the advise so far is not valid and I know what Holley specs for secondary are. You said it ran great before the change. So why not go back to the beginning. Personally I always keep the secondary on a DP closed as much as possible (not to bind). Look down the inside to see if back venture is dripping at idle. There should be no drips if the floats setting is correct. If they drip close the sec. up.

6.5 PV sounds too loose for a big cam. It's beginning to open at around 13psi vac.(stinky idle) Go smaller to maybe 4.5. With a Mike-like cam you may need to remove the PV and plug it and just jet up a few sizes.

Holley chokes just suck. They start closing a few min. after the 12v juice quits flowing no matter how hot. Slow to reopen (making hard starting and flooding) Wire the choke open if not needed in the summer.

Engine stumble can be most anything from like timing (per Mike) or acc. pump shoot
to little
to much
to late
no long enough
and there should no acc. pump play or binding at WOT. Just idle.

I did say it ran before the change, but the Extended Crank has AL:WAYS been an issue...Very Bad Hot Extented Cranking, so I attributed it to the secondary butterfly curb idle setting.....Once I starter the removal I had noticed the Throttle Lever (and then obviously the Cable to primary butterfly setup) was not reaching full travel, so I then made the assumption that all idle settings were made to accommodate the travel issue, so I started over!.....

***The Car Starts Cold Perfectly, CHoke set nicely, Idles are Nice (but noticeably stinkier Idle than before---trying to fix that bug???---) and As Per SALLY:
Finally had the Timing Set and Values Known......A random cruise to my brothers place, His neighbourhood who is a Old Racer/Hot Rodder and I got to talking and he helped me out.  Had a Beauty Snap On Timing Light.........11deg Initial and 43adv, said you're good and in a sweet spot. He feels we moved the Starter in and around 1/2" which as you all know is A LOT!

So update from this is: Cold Start and Immediate Restart within couple min or less is improved, seemed to catch faster.  Much Notice power and responsiveness improvement.  Car rolls out of first gear much smoother and easier: All Gears at lower RPM range and much more responsive!

HOT START ISSUE remains!  Embarrassingly Long Hot Start even after 4-5min of sitting.

So whats next? 
I just ordered a Wood Spacer and The Neighbour suggested looking into Spark Plugs with Required Heat Ratings?  does this sound Right to Anyone?  Other than these 2 variables I dont know what to do Next!

Sound like the acc. shoot falls short and needs to be extended longer. A carb. cam with longer or maybe steeper ramp or the one you have now (what ever it is) can be moved to a different  screw hole.

I think hot start problem again is the choke has closed after a few minutes and flooding the carb. Hope your not pumping the accelerator when it's hot. It's only going to make it worse. Foot to the floor and hold it there till it starts

6sally6 wrote:

Did you ever 'share-with-us' info about your ignition timing.....ignition curve....total advance...etc.?
Many times a "hesitation" can be cleared up with timing tuning. Engines with "a bit of a cam" need a good timing curve to ever run right.
Jus say'in!
6sally6

***The Car Starts Cold Perfectly, CHoke set nicely, Idles are Nice (but noticeably stinkier Idle than before---trying to fix that bug???---) and As Per SALLY:
Finally had the Timing Set and Values Known......A random cruise to my brothers place, His neighbourhood who is a Old Racer/Hot Rodder and I got to talking and he helped me out.  Had a Beauty Snap On Timing Light.........11deg Initial and 43adv, said you're good and in a sweet spot. He feels we moved the Starter in and around 1/2" which as you all know is A LOT!


knowing this, whats your thoughts?  any Merit to the TEMPERATURE ratings of the spark plugs?

I coming to this discussion late and may have missed suggestions in previous posts, these are things I suggest...
I have a Holley 600 DP and do not have issues w/hot starts; with electric choke, a 1/2" phenolic spacer between the carb and manifold and an MSD distributor w/o vacuum advance.
My initial timing is 12-14 degrees.
The electric choke works well, opens a little too quick for me, but I can deal with it, and will close quickly when power is tuned off.  With the hot engine I've found that not touching the gas pedal seems to work well when starting.
I suggest that when the engine is hot, remove the air cleaner and see where the choke is, have someone hold it open or somehow mechanically hold it open.  Try starting w/o touching the gas pedal to see if the issue is a lack of 'air' getting into the engine, or a flooding condition.
Also, with a hot engine shut off, check the float levels.  If the gas is gone, or low in the bowl, and no active leaks are detected the fuel is either going into the engine or back to gas tank.  Look into the carb and see if the throttle plates look "wet", as this is an indication that fuel is being drawn into the engine.
Looking at the picture of your engine in earlier posts, maybe the fuel line and filter are experiencing 'boiling", you may want to try running a temporary hose from the pump to the carb to see if that is the cause of trouble.
Are you checking the initial timing with the vacuum advance isolated from the distributor?
Again looking at the earlier picture of your carburetor, I see the vacuum advance is connected to receive carb vacuum, verify this is correct as I believe it should be connected to receive manifold vacuum.  This port is just below the front fuel bowl and in the picture appears to be unplugged, if not used this should be plugged.
If fuel is being drawn, or forced, into a hot engine, going to WOT w/a DP'r only puts more fuel into the engine that will require additional cranking to clear the flooding condition.
What is your vacuum at Idle and what temperature does your engine run at?
 

6sally6 wrote:

What are your spark plugs gapped at?!
6s6

no Clue, but I will look into it....the engine build cost just shy of $8,000CAN done by a pro engine shop.  Once again I can only assume they are proper. 
Can you recommend a Plug for a High-Po 302, Edelbrock Performer Heads?

Furthermore to answer choke hot start setting/closing theory.....This Carb had Very Bad Hot Start Purchase 4 months ago; It had a wire Locking it in the OPEN Position. 
3 things Im trying to rectify are :

-Extended Hot Starts that only seems to work with the Pedal at WOT
-Smelly Idle (which I think I have corrected very well by adjust secondary curb Idle Screw and Leaning the Mixture Screws
-Light Hesitation during Low RPM

Sally I will Report Back on the SP gap