1966 Carter AFB starving for fuel?

[TylerW]

Hey all:

I've had a long-term issue with the carburetor on my '66 300 383, which is the original 4131S. It works perfectly "most" of the time, but it appears to run out of fuel when I am in the secondaries. I don't drive this car hard but there are times when I need the power(and other times I just like hearing the 4bbl kick in lol). I get about 2 seconds of full power, then it starts losing power. If I keep my foot in it, it will level off about 70mph.

However... I conducted an experiment and disconnected the linkage to the secondaries and went for a drive. Running on 2bbl only it will wind out each gear with no starvation. BTW it's a fairly fresh engine...not trying to push an original engine that hard.

Here is what I have done. Part of this was related to getting the car back on the road 4 years ago:

New fuel tank and sending unit
New fuel line
New Carter fuel pump
New hardened fuel pump pushrod from Mancini(the old one was fine)
New line to the carb
New fuel filter
Rebuilt carb twice, blew all the passages out, set the float height by the book
Rebuilt the distributor and installed a Pertronix unit and matching coil
Modified a stock ballast to provide full voltage to the coil
New plugs, cap and wires

I'm at my wit's end with this thing. That carb is simple...I don't know what I could have missed or the issue is elsewhere.. As I said it runs perfectly otherwise except that it dries up after sitting a few days, and it is VERY prone to heat soak in the summertime. Maybe those are clues? Thanks for any advice.

 

[CBODY67]

Just curious, I suspect you replaced ALL of the rubber fuel line at the three places in the fuel supply system? At the tank. At the rh rear of the stub frame? Supply line for the fuel pump?

In the carb rebuilds, did you re-use the orig needle and seats or put in the ones in the kit? Did the hole in the middle match the OEM items?

On my '67 Newport 383 4bbl, never had any issues as you describe. Considering the size of the AFB/AVS float bowls, hard to visualize that only two seconds of WOT would empty them. Even if they might be slow to fill. Presuming the OEM secondary jets are still in place?

Presuming the ignition system was refreshed with the engine work? Which air cleaner?

Just curious,
CBODY67

 

[marty koirtyohann]

Hey all:

I've had a long-term issue with the carburetor on my '66 300 383, which is the original 4131S. It works perfectly "most" of the time, but it appears to run out of fuel when I am in the secondaries. I don't drive this car hard but there are times when I need the power(and other times I just like hearing the 4bbl kick in lol). I get about 2 seconds of full power, then it starts losing power. If I keep my foot in it, it will level off about 70mph.

However... I conducted an experiment and disconnected the linkage to the secondaries and went for a drive. Running on 2bbl only it will wind out each gear with no starvation. BTW it's a fairly fresh engine...not trying to push an original engine that hard.

Here is what I have done. Part of this was related to getting the car back on the road 4 years ago:

New fuel tank and sending unit
New fuel line
New Carter fuel pump
New hardened fuel pump pushrod from Mancini(the old one was fine)
New line to the carb
New fuel filter
Rebuilt carb twice, blew all the passages out, set the float height by the book
Rebuilt the distributor and installed a Pertronix unit and matching coil
Modified a stock ballast to provide full voltage to the coil
New plugs, cap and wires

I'm at my wit's end with this thing. That carb is simple...I don't know what I could have missed or the issue is elsewhere.. As I said it runs perfectly otherwise except that it dries up after sitting a few days, and it is VERY prone to heat soak in the summertime. Maybe those are clues? Thanks for any advice.

i had the same problen with my 71 440 i had a fuel piump ppush rod that a bit too short (the1st owner had got the motor really hot , when i remoed the push rod ir was BLUE! THATS HOW HOT IT GOTi replaced it & nomore fuel starvation

 

[marty koirtyohann]

Hey all:

I've had a long-term issue with the carburetor on my '66 300 383, which is the original 4131S. It works perfectly "most" of the time, but it appears to run out of fuel when I am in the secondaries. I don't drive this car hard but there are times when I need the power(and other times I just like hearing the 4bbl kick in lol). I get about 2 seconds of full power, then it starts losing power. If I keep my foot in it, it will level off about 70mph.

However... I conducted an experiment and disconnected the linkage to the secondaries and went for a drive. Running on 2bbl only it will wind out each gear with no starvation. BTW it's a fairly fresh engine...not trying to push an original engine that hard.

Here is what I have done. Part of this was related to getting the car back on the road 4 years ago:

New fuel tank and sending unit
New fuel line
New Carter fuel pump
New hardened fuel pump pushrod from Mancini(the old one was fine)
New line to the carb
New fuel filter
Rebuilt carb twice, blew all the passages out, set the float height by the book
Rebuilt the distributor and installed a Pertronix unit and matching coil
Modified a stock ballast to provide full voltage to the coil
New plugs, cap and wires

I'm at my wit's end with this thing. That carb is simple...I don't know what I could have missed or the issue is elsewhere.. As I said it runs perfectly otherwise except that it dries up after sitting a few days, and it is VERY prone to heat soak in the summertime. Maybe those are clues? Thanks for any advice.

OK HOW LONG BETWEEN START UPs ? how long dose it set?

 

[marty koirtyohann]

Hey all:

I've had a long-term issue with the carburetor on my '66 300 383, which is the original 4131S. It works perfectly "most" of the time, but it appears to run out of fuel when I am in the secondaries. I don't drive this car hard but there are times when I need the power(and other times I just like hearing the 4bbl kick in lol). I get about 2 seconds of full power, then it starts losing power. If I keep my foot in it, it will level off about 70mph.

However... I conducted an experiment and disconnected the linkage to the secondaries and went for a drive. Running on 2bbl only it will wind out each gear with no starvation. BTW it's a fairly fresh engine...not trying to push an original engine that hard.

Here is what I have done. Part of this was related to getting the car back on the road 4 years ago:

New fuel tank and sending unit
New fuel line
New Carter fuel pump
New hardened fuel pump pushrod from Mancini(the old one was fine)
New line to the carb
New fuel filter
Rebuilt carb twice, blew all the passages out, set the float height by the book
Rebuilt the distributor and installed a Pertronix unit and matching coil
Modified a stock ballast to provide full voltage to the coil
New plugs, cap and wires

I'm at my wit's end with this thing. That carb is simple...I don't know what I could have missed or the issue is elsewhere.. As I said it runs perfectly otherwise except that it dries up after sitting a few days, and it is VERY prone to heat soak in the summertime. Maybe those are clues? Thanks for any advice.

how much fuel flow do u have? have u tun a flow test? a good rule of thump if u can fill a quart jug in 60 seconds or less u have enough flow. dose yur car have a return line from the filter to the tank?on some late 60 b bodies had a return line & a screen if the screen is plugged u will have a running issue . is te timing set right? the avs is a simple carb , but there r certain parts that r needed to make it run right. was te carb a new carb or auded one?could u be someone else screwed it up be4 u got it?
my cousin & myself had a 68 charger rt se . his cousin bought it from a action as a running car , the csrb was all screwed up .it too was "rebuilt" it had parts missing floats was set way too low , timing was way off . it too would not run right . it ran out of gas on the rod ,. i dont know how many carbs u have rebuilt . maybe u need s good carb gy to check it out ? r u sure u dont have a hole in the fuel line or a plug filter someplace? . all tings to check

 

[NitrousTuner1]

What's total timing set at?
The factory tune of the A/F ratio is not close to optimum. Are the metering rods & jets factory still or has it ever been professionally tuned?
Have you ever been in the secondaries & shut the engine off... Coasted off the side of the road & pulled plugs to see IF they were bright white & lean???
IF so how close to optimum was the timing mark on the ground electrode?
Are you baking that cast aluminum heat sink carb with a factory cast iron skillet intake?.?.?