Carb sputtering on six barrell engine

[clazar]

I got a 1970 440 + 6. Just finished new 440 Source aluminum heads. Car starts just fine. But when i give it some gas under load the engine sputters & wants to die. Choke seems to be working fine, I just checked & adjusted the floats. What else should I check to correct the problem. Could it be a bad accelerator pump.

 

[R413]

Yes it could be accelerator pump.

is there any exhaust heat in the intake? Blocking that can cause it.

was this 6 pack running with iron heads before the aluminum heads?

 

[clazar]

Yes it could be accelerator pump.

is there any exhaust heat in the intake? Blocking that can cause it.

was this 6 pack running with iron heads before the aluminum heads?

It did have iron heads before the swap. Now aluminum heads & intake.

 

[Ron H]

Another possibility is engine timing. Carbs new or rebuilt? Ok, simple stuff ya may know; just tossing this out.

 

[clazar]

Another possibility is engine timing. Carbs new or rebuilt? Ok, simple stuff ya may know; just tossing this out.

Carbs were rebuilt 7 years ago. I never retimed it after aluminum heads were installed. Never had this problem until after new heads.

 

[WileERobby]

How are all your vacuum hoses/connections ? Accelerator pump ? Vacuum secondary pods/linkage ?

 

[clazar]

How are all your vacuum hoses/connections ? Accelerator pump ? Vacuum secondary pods/linkage ?

All vacuum hoses good. Linkage is not binded. Accelerator pump ?? I don't know how to check that. I can cruise good with the car. But if I hit the gas hard & fast it sputters & wants to die. It's an automatic. I'm not taking it down to passing gear. Just to that point.

 

[Photon440]

To check your accelerator pump, remove the air cleaner so you can see the center carb. Open the throttle by hand and watch to see if fuel squirts from the pump nozzles. It should squirt immediately upon rotating the throttle plates.

Some engines can stand a little more timing advance with aluminum heads.

 

[Austin Charger]

I got a 1970 440 + 6. Just finished new 440 Source aluminum heads. Car starts just fine. But when i give it some gas under load the engine sputters & wants to die. Choke seems to be working fine, I just checked & adjusted the floats. What else should I check to correct the problem. Could it be a bad accelerator pump.

Power valve in center carb may be contributing. Diaphragm may be hardened from age. Passages plugged. If you are going to take carb apart order non stick blue gaskets along with new power valve.

 

[R413]

440 source stealth heads don’t have a heat crossover. This is a potential problem until the intake gets warm.

drive the car for 30 minutes and then see how it works.
now park it for 15 minutes with hood closed and out of the wind. Now go drive it and see how it works.

 

[Mopar Miki]

Six paks are not washing machines, they need to be set up for the application. Lack of manifold heat has nothing to do with your problems, you want the manifold heat blocked off anyways. 195 Thermostat to start and down the list you go Go to the lift off hood playground and get the six pak tuning guide

 

[PurpleBeeper]

I got a 1970 440 + 6. Just finished new 440 Source aluminum heads. Car starts just fine. But when i give it some gas under load the engine sputters & wants to die. Choke seems to be working fine, I just checked & adjusted the floats. What else should I check to correct the problem. Could it be a bad accelerator pump.

My first bet is accelator pump...make sure it squirts like mentioned above by just looking and moving the throttle

 

[WileERobby]

I've been running 6-bbl for 50 years. In various configurations. Almost always heat passage blocked, never a problem.

 

[BSB67]

Rebuild the center carb.

 

[R413]

If the carbs are set up for blocked manifold heat that’s great, if they are not this could be a problem. Not so much on a racecar with compression, big cam and lots of fuel.

Has anyone ever has a small block mopar with the intake heat passage plugged up with Carbon? The car runs terrible. Then when you remove the intake and clean out the passage the car runs good again.

 

[clazar]

I think I finally found the problem. The choke wasn't opening fully after warm up. I disconnected the choke & wired it open. Took it for a ride & she ran perfectly. I think the culprit might be the choke pull off. Is there a way to test it before replacing it ??

 

[WileERobby]

I think I finally found the problem. The choke wasn't opening fully after warm up. I disconnected the choke & wired it open. Took it for a ride & she ran perfectly. I think the culprit might be the choke pull off. Is there a way to test it before replacing it ??

Just observe it to see if its functional.

 

[Ron H]

With the choke connected, open and close it to make sure it has full travel - no binding or sticking linkage