327 with 4mv quadrajet- after driving for a while at highway speeds, i put in the clutch to slow down, and while coasting to a stop, the engine stalls. When it does stall, it takes 10 -15 seconds of cranking before it will start again.

It feels like it is fuel starved, but pumping the pedal won't save it from stalling once it starts to sputter

My choke is currently disconnected (project for another day) but I have confirmed that it is open.

I rebuilt the carb a few weeks ago, and the problem has remained the same. I bumped the idle speed up a bit, hoping to lessen the problem, but it still stalls.

I just drove a parade, and had no issues at slow speeds. I think it is significant that it happens after a longer run at cruising speed (floats, maybe?)

 

You add alittle more fuel to the bowl, and ensure the float is at the right height first.
The other action you could do is wrap the fuel line with insulation as fuel may be percolating.
Attach clothespins to fuel line and ensure the line on subframe is mot hitting or too close to exhaust header.

 

I agree that vapor lock is a very good possibility but I have seen heat effect both coils and condensers in this way.

 

Thanks, I will look into it. It seems that most of the times it happens is in the middle of a hot afternoon

 

Good suggestions. Thanks for your reply!

 

Still haven't fixed the issue, but I'm convinced it is vapor lock. I idled it for 10-15 minutes, revving the engine hard at times. it stalled without warning. When I opened the carb, it was bone dry. checked for line blockage, and there was none. Reassembled, started first try.

Currently deployed, so won't be doing this for a few months, but trying to research it from a distance.

Would an electric fuel pump solve this (in-tank or inline)? If so, any recommendations on brands/types/sizes, etc?

 

Is there an inline filter anywhere that might be clogged?
Are you sure the fuel pump is good?
Old rubber fuel lines can crack and suck air or collapse and block flow, how old are they do you know?
Electric pumps work great, I think I had a Carter on my '69 big block car feeding a Holley 750 double pumper, never an issue getting fuel, also had a pressure regulator inline.