427SIXPACK

STALLING

Finally a nice somewhat warm sunny day here in the North East
broke the red head away from the garage.

Need some suggestions ??? started up a bit rough then, evened out. Ran great for 15 minn or so, then started stalling everytime I stopped.

Turned key started right back up & idled fine most times / low at others but didn't stall. Drove until next light fine then I stopped / whamo / stalled again & starts right back up ? 4spd so I cant be in the gas / brake /on a hill / stop/ all at once !!! only got 2 feet

what do ya think ?

427SIXPACK

ttt

427SIXPACK

no one ? all you awesome mechanics / no ideas ?

Rky Mtn C6

My 78 did that when I ran premium in it. Went to 85 and it stopped.

capevettes

My guess is you have some debris clogging up the needle and seat in your center carb. I have had good luck pulling the needle valve and blowing it out with an air compressor or even blowing it with my mouth.

427SIXPACK

I run 110 / anything less it don't move !!! & farts like grandma & grandpa

427SIXPACK

Mystery still a mystery ................. unresolved !!! GRRRRRR

BKbroiler

Very likely a carburetor problem. Fuel octane has nothing to do with it.

ORANGEBROTHERS

My L36 did the exact same thing for a while then it cleared up it was a bit of dirt in the fuel system. Also could be a vacuum issue so check the lines as well...

jnb5101

Something simple like a float level issue, plugged fuel filter or water in the tank?

69Pman

Did you store it over the winter with a full tank and a fuel additive like stabil storage? When we first brought the vette home after purchase, the tank had little fuel in it that had been sitting for a while. Ran good for about 10 minutes and gave sputters here and there and then stalled every time I came to a stop or at low rpm. Learned how to keep one foot on the clutch and use the other to hold the brake while edging the gas pedal to keep the rpm's up in a hurry to get it back home. Opened the gas lid and you could literally see the moisture. Filled it with some additive, topped the tank off, and ran it out of her. Took little while but she runs flawlessly now. Don't know if that's what you're up against but its worth asking about if nothing else is working. Good luck.

LS4 PILOT

Did you take a few plugs out and see how they look. Might give you a clue .

Fuel filter .

I just changed mine .

427SIXPACK

everything new last summer
wires
cap
rotor
points
plugs
alt
reg
but have not checked plugs

joewill

idle circuit somewhat clogged,
fuel pressure too weak to fill bowl causing stalls.

black smoke after restarting after a stall? then flooding from stuck open needle and seat
if no black smoke then lean stalling, low float or clogged idle circuit

take her out for a good exercise, that solves 90% of after storage problems.

427SIXPACK

took her out drove 70 mph & got in it hard a few times drove great no issues/ got off highway all was well, no stalling at the next bunch of lights either better then many previous rides, BUT ..................
parked turned off, sat for 3-4 hours, then hard start crank crank crank VROOOOM ..............started drove 10 feet stopped to check traffic before pulling out / stalled, started right back up, next red light stalled, ....................UNREAL !!!! no smoke at all / no gas smell, but it smokes starting cold & rough then clears up.

gungatim

does it ever idle properly? if so what RPM is idle set to? does it idle when cold w/choke on? this will point to vacuum leak, low speed mix too lean, clogged idle circuit, incorrect timing...you just had the carbs off right? (from other post), check for vacuum leak at base gasket...

Z06FEVER

Could be ignition related. What are you running, points or electronic?

427SIXPACK

points / car is all stock

Z06FEVER

I know that Hei ignitions modules going out cause symptoms as you described but I'm not sure if points would do that if they were not working properly. I'm just not sure you have a fuel problem with it being intermittent. Fuel usually will keep the problem around all the time and ignition can play games by working and not working. Just my thoughts so I hope you get it fixed.

tomdoc

Good morning Sixpack, Don't you just hate it when no body responds to your question! Especially when your trying to fiqure something out ASAP !! I am also in the process of fine tuning my carbs. I had a similiar situation last year year as you. I have found that optimum idle starts with correct idle timing FIRST !! Then try adjusting the air bleed screws on the low speed idle circuit. It's a quick and easy first step. I found after rebuilding my carbs, the main carb of my tripower setup is very, very sensitive to as little as a 1/4 turn either way. Holley specs are to set the initial adjustment at 1 1/2 turns out. I've seen some carbs that like as much as a 1/2 turn in (closed/lean) to as much as 1 1/2 turns out (open/rich). My motor seems to like being right at 1 1/2 out. Holley recomends adjusting to max vacumm at idle. I haven't used a vacuum gage to set mine because she idles well and is clean and crisp of idle. My issue I'm battling now is the proper operation of my outside (secondary) carbs coming on.... Tom.