Holly 4000 Teapot Stumble - HELP !!!

Oldmics

Oldmics

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I"m gonna post this question on a coupla Forums.
I know there are some really good carb guys out there.


So heres the story. Holly 4000 teapot that stumbles off acceleration.
I know these carbs really well (apparently not well enough) so I have addressed all the usual items.




Float level is adjusted properly,fuel level is correct. It starts and runs with no problem. It goes like hell if you mash it to the floor.


Its just got this off idle hesitation on normal gas pedal pressure.


The pump shot is slow on accelearation. I have replaced the accelerator pump and rod assembly (twice).
There is a pump discharge needle that I have discovered comes in some different lengths and weights.


I have tried different pump discharge needles with no success.


The pump link lever is positioned in the short hole allowing for an immeadent and longer pump shot.


I have a good pump shot but its not immeadent enough.


Could this be the butterflys opening before the pump shot?


My question is "Is there anyway to hasten up the pump shot" ?


Thanks to all.


Oldmics
 
Oldmics,

It sounds like you have covered a lot of the normal possibilities for the problem. One other thing I can think of for a delayed pump shot would be if the spring that is on the pump rod (inside carb) is missing and the rod can't go all the way up when returning to idle. Then the first little throttle movement off of idle takes up some slop making a delayed shot. Or if the pump rod is tight in the 1/4" hole in the bowl it won't return all the way up.
Possibly the check ball in the bottom of the pump bore is leaking and blowing some fuel back into the bowl and not out the discharge jets.

Also, make sure the ignition timing is correct at idle. From my experience, I like about 10 degrees BTDC.

Sal
 
Have you checked for wear/looseness in the linkage? Does the pump plunger move immediately?
On another note, try a tank of real (non-ethanol) gas. Ethanol has the effect of leaning out the fuel mixture and may be causing a lean stumble, especially if the pump shot is a little weak.
 
Don't know the history, but if you or someone else has changed to smaller primary jets, this can affect response. I assume you have already made sure the gas path for the accelerator pump is clear by plunging with small drill or wire and then using carb cleaner and blasting for flow. Hope you respond when you figure it out.
 
So what's up John ? Get it fixed ? Feedback rules. Don't know about anyone else, but I'm curious as heck.

Sal
 
Not fixed as of yet :mad::mad::mad::confused::confused::confused:

Hoosier has given me a suggestion and I had to order a tool to give it a try.

I will report back with the outcome.

I did speak to Tim at Daytona carbs and he also offered a few insights on things inside of these carbs that I never knew about.

I"ll share all that later.

Still in the battle.

Oldmics
 
I had a similar problem with my "Teapots" (I run 2 of them).
My friend came over, opened the idle adjustment screws 1/2 turn
on each carb & the problem went away. Might be something to try.
Jim
 
Yes like Kahuna mentioned, this is what I do as well and I run two teapots as well with great success!! I tweak the idle screws to a very slight rich not to the point of having a lousy but smooth idle and I also run my timing as close to the limit as possible using the ping drop method IE advance until engine pings and retard till very slight pinging occurs under hard load such as pushing hard on the brake while in gear and give the gas pedal a quick tromp. My Continental is a Bearcat for premium fuel so I use the highest premium available which is lousy 91-92 octane with the ping drop method and then I use a good quality octane boost to clean up any excessive pinging even with the timing less than what it should be because the good gas this car used when new is long gone:(
Lots of people criticize the teapot to the point of converting the 56 Mark II from a Holley to a Carter that was used in 57 and I feel this is stupid because like Kahuna mine works fantastic to the point of when the engine is warmed up, just twitching the ignition key to start and snapping it back to run position is all that is needed to start my 368 with no stumble whatsoever.
My second teapot? It's actually the grandfather teapot to the 4000. It's a Holley 885FF an early 2 barrel version with automatic choke used on my 50 Mercury Sport Sedan of which I've owned for over 30 years with the same carburetor.
Make sure your timing isn't too late, tweak your idle mixture, and if that doesn't work even if your accelerator pump is working fine, take a peek at your main jets of your primary side to see if somebody in the past was chincy with fuel. Also what condition is your engine in? Good even compression?

Don
 
I run a teapot on my 56 Bird (original carb) and it works with no problems. Had it professionally rebuilt by a teapot expert.
 
I had a similar problem with a later 64 FE in a T-Bird. It turned out to be a distributor problem. The distributor had enough wear in the bushings that it would effect off idle response and would miss every now and then just out of the blue. It would purr along for quite a while then miss just once. The distributor had just a little play but it was enough to cause a little problem that annoyed the hell out of me. Poor advance response can also cause off idle problems.

You mentioned what carb you have but what year and model of engine/car is it with?
 
Oldmics,

Any luck yet ? What was the tip that Hoosier Hurricane gave you where you needed a special tool ?

Sal
 
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