truck randomly stalls out, but runs perfect otherwise.

[yellow400ex05]

Alright I recently installed a new Quickfuel 780cfm carb on my truck that has a BBC. electric choke vacuum secondaries. today while driving it in 20 degree weather it warmed up fine drove down the road okay but it would stumble at low throttle. as if it was trying to stall for a split second, but it accelerates fine pulls hard plenty of fuel, idles nice. timing is good all was fine a couple days ago.

now when i have it in gear or idling is when it will stall, and it doesn't spit and sputter then dies, it just dies, as if you shut the key off. to start it back up it'll just crank unless i put the pedal to the floor. would this be choke related maybe?

i checked the choke and its not sticking on, or anything.

could a bad ignition switch cause this?

the truck turns over every time though. starts right up, unless you try it right after it stalls out, then you obviously have to hold the gas pedal down..

[geezer#99]

If you need to put the pedal on the floor to start it, it means only one thing!
Flooding!!

[clapage6]

yep, check float level and clean or replace the needle + seat

[yellow400ex05]

here's where my float level is.




here's a video
http://tinypic.com/player.php?v=2h7j...8#.Uw6kk86mXH4

it also stalled on me while coasting down a hill in drive tonight, it just quit had to pull over and re-start it and it started right back up.

[geezer#99]

Too high.
Lower it down below halfway.

[yellow400ex05]

i just watched a video on how to adjust the floats on a holley carb and it seems pretty tedious for someone whom has never done this.

[yellow400ex05]

could very cold weather affect how it runs as well? i had it out yesterday and it ran fine, mid day just above freezing, and i went out today and it was 20 degrees out, the floats and mixture screws were all adjusted when it was 45-50 degrees.

[yellow400ex05]

just had it out again, and it stalled out multiple times this time and the temp is now 8 degrees.

[yellow400ex05]

Actually insidious, i really dont think its loading up and dying, i know what thats like, it woul blow black smoke when re-starting it and you'd have to clear it out, turns out i was wrong when i said i had to hold the pedal down to start it, it will still fire back up immediately. it seemed worse this last time i went out it stalled more, and backfired a couple times as it tried to stall while driving through my neighborhood. I'm beginning to think its fuel related, i kjnow the carb runs on the rich side, but it shouldnt just die instantly if this were the case. when i say idling i mean it could happen as soon as i slow down or 5 minutes after i stopped. I'm going to check my fuel pump and maybe even replace it, It hasnt been driven much the last several years and i've put 1,000 miles on it in a month now. and the engine has been in it since 1989. it doesnt make sense to me that the truck would suddenly the following day start to do this if it were float related it would sputter before it died not instantly quit. im almost tempted to say i felt very slight surging last week while driving it after i got the carb on it. I did go from a 650CFM carb to a 780CFM so its pushing out a lot more fuel for it since its a cammed up rebuilt BBC. so what do you all think?

then again it doesnt seem like a mechanical pump would start to fail by still running and idling fine, and stalling suddently either, that seems like it would be more related to an electrical one lol ahh i hate issues like this sometimes..

[INSIDIOUS '86]

Cold weather will lean it out and make it harder to drive yes
I you can change a wheel you can set the floats

Loosen the lock nut/screw some while the engine is running and tighten the needle valve till the floats are a little halfway.

Make sure you run a filter as well.

When your idling it's loading up with fuel and dying.

[yellow400ex05]

Originally Posted by INSIDIOUS '86

Cold weather will lean it out and make it harder to drive yes
I you can change a wheel you can set the floats

Loosen the lock nut/screw some while the engine is running and tighten the needle valve till the floats are a little halfway.

Make sure you run a filter as well.

When your idling it's loading up with fuel and dying.

okay does the engine need to be warm or cold, and on an incline?

[geezer#99]

WArm enough to idle and sitting level.

[yellow400ex05]

Guy's instead of blowing this forum up for now I'm going to start with the easiest things and work my way down the list here, starting with the fuel filter, its clearly pretty old and it is not a transparent filter so who knows how bad it may be. if this fixes it ill be so happy. after all it coulld be likely its been there since 1989. truck had 65k miles when i bought it and had only 50k or so miles back in 2000. engine was put into the truck at 43k miles.

thanks for the help though i know where to start, and what to check now so wish me luck if i have anymore questions after i change the filter I'll get back to this thread.

[INSIDIOUS '86]

Mine did this when I got my new hei. Turns out msd makes crap coils. Go over your ignition and see what turns up.

[Gumby]

^ all those epoxy filled in cap coils are prone to fail from the start, epoxy holds in heat, #1 enemy of ign parts, heat.

get the external coil HEI cap, so you can use a good oil filled can coil.......