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The car is cutting out at half track on the 1/8th mile

SteveSS

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It has a mechanical fuel pump that we replaced today. It's doing great then all of a sudden it falls flat on its face. We can rev it big time when it's parked.

Here's what some said:
Needs an electric fuel pump
Float bowls not set high enough
The coil is not powerful enough

We are running a Carter AFB 750 at 6000 feet elevation. When we let off the gas it seems to catch itself again. Ideas?
 
It has a mechanical fuel pump that we replaced today. It's doing great then all of a sudden it falls flat on its face. We can rev it big time when it's parked.

Here's what some said:
Needs an electric fuel pump
Float bowls not set high enough
The coil is not powerful enough

We are running a Carter AFB 750 at 6000 feet elevation. When we let off the gas it seems to catch itself again. Ideas?

The suggestions above have merit. Those AFB's are great carbs it's just the fuel bowels are a tad on the small side, thirsty BB can suck one dry in no time. Sounds like fuel starvation during WOT, maybe upgrade to a HV mechanical or electric pump/regulator set up to keep up with demand. Check float height and make sure the needle and seat are doing their thing, replace the filters while your at it. :thumbsup:
 
There is nothing the matter with AFB bowl size. They are plenty big enough. How did it run before the fuel pump swap? Is the tank vented? Do a volume test . Itll run for a bit with the line disconnected. See how much fuel it pumps into a jug vs time running. Report back. It may need more pump. Its possible the floats off but unlikely. I set them to 7/32" instead of the recomended 7/16"
Doug
 
I always like to run a electric pump near the tank to push the fuel to the mechanical pump. A electric pump on a switch with a 2 to 4 PSI is plenty and no regulator is needed. That's what I run on my Hemi car. If I fail to turn on the pump and a WOT run I know it in a hurry. Works for me.Also helps with vapor lock in high heat. Just a thought.
 
This is a little hard to nail down in one answer, but this is a “What would I do” thing...

Check float setting and adjust a little lower and test.

Still a problem? Less a Problem?

Electric fuel pump. I used an Edelbrock electric fuel pump for a carb. Low PSI vs a FI pump. It is designed for there carbs. Get the relay with it. EZ to install.
 
Going with weak cool output at higher rpm
under load
 
Wild guess here- worn fuel pump push rod ?
Agreed. First thing I'd do is pull the rod out and see how close to 3.22" it is and go from there. Been there with that same symptom and that's exactly what the problem was.
 
Step 1 - Put a gauge on it and see what it does at WOT.
 
It has a mechanical fuel pump that we replaced today. It's doing great then all of a sudden it falls flat on its face. We can rev it big time when it's parked.

Here's what some said:
Needs an electric fuel pump
Float bowls not set high enough
The coil is not powerful enough

We are running a Carter AFB 750 at 6000 feet elevation. When we let off the gas it seems to catch itself again. Ideas?
I guess the obvious question would be was it doing this before the fuel pump change? or after?
 
my 1st thought was ignition weak spark
(timing too far one way or other, usually advanced)

#2 &/or weak bad coil, shitty dist. cap, something arching etc.
#2a shitty plugs, fouled &/or wrong heat range & gap for type of ignition

#3 **** plug wires, or arching or loose electrical wires to ignition or coil
12vt power source
#3a detonation, big time, easy at altitudes

#4 thought is lean as **** at the top of the gears, not getting volume needed
#4a fat/rich as all **** (you're at altitude after all) need to see the plugs

#5 either carb is set/tuned wrong or total ****

#6 or pump isn't doing it, dropping off psi/volume/flow or total ****

#7 too small of a fuel line 5/16ths or collapsed or rusted old crap or total ****

#8 tank not vented well enough, no vented cap &/or clogged vents

#9 or sender &/or pickup/sock (stock tank) is clogged or both are total ****

#10 ****/debris clogging the fuel filter under a load, not getting flow needed at RPM

doubtful but possible
#11 valve float, or old used weak valve springs
#11a wrong or worn camshaft
#11b collapsed lifter/lifters pumping up or too lose

#12 6000' altitude doesn't help either

check the most logical & easiest 1st
 
Last edited:
Do you have the sock filter in the gas tank on the pickup? If so...look there first.
 
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