How well does your blow thru start cold (by cold I mean engine not up to temp, first start of the day) ? I'm in the initial tuning/tweaking stages with my Quick Fuel/ CSU blow thru 650 and it doesn't start all too well and wont idle on its own when cold. Obviously I know it won't be like a fuel injected car, and that's fine. I have adjusted my idle mixture screws when the motor was fully warmed up, and it idles near 13.5 AFR with the engine fully warm, and runs clean and crisp like this. However, now the cold starts aren't great, and it shows pretty lean on the AFR gauge while warming up, anywhere between 14.5:1 and 16:1 give or take. I usually have to keep my foot on the throttle for at least 3-4 minutes....and probably have to re-start the car 4-5 times. I thought it would be slightly better than this...how well does yours fire up?

 

Mine were about the same (or worse), and it's one of the main reasons I went to efi. I'm not sure where you're at, but here in Mn we have a lot of those days.

 

I'm in Indiana and only drive it on nice weekends mostly so its not a daily driver or anything. It's been about 50-60 degrees here lately. No problems whatsoever starting when warm. I'll keep playing with it a little at a time.

 

I live in CT. 5.3 chevy with 600 holley and turbo. I did the hanger 18 stuff to it. The carb is pre 1992. If its 40 deg, I hit the key and by the 3rd pump of the gas, its running. I have to hold it at 1500 RPM for 45 seconds to 1 minute. It will then idle at 650 RPM. Its 15 seconds of holding gas in summer. Mine has 21 inches of vacuum at idle and AFR is 14;1. I can get it to 14:7 at idle but it runs rough. I think carbs like 14:1. This is with a victory jr open plenum intake. If you have a big cam in there, all bets are off.

 

on the holey carbs i like to leave the manual choke linkage on the side of the carb so i can pull a cable and still idle it up when its cold

 

Mine does pretty good. Probably 30 seconds of keeping it running and it'll idle fine.

 

My junk seems to be doing better now that outside temperature has warmed up into the 70's. I can get it to start and run without dying at all now, just need to keep a foot on the gas for 45 seconds or so. Typical carb stuff

 

I had similar issue with the c and s carb on my 363...it did not like 13.5 at idle warm at all as I adjusted it closer to 13 it starts with two pumps right up

 

Mine starts good down to about 30 degrees and that's on e85. Just a little pedal blipping and keep the rpm about 1200 for 20-30 seconds and it will idle on its own fine. Afr is about 12 as that's what the cam likes so I'm sure that part helps.