Carb queery's

[rumblefish360]

OK, backround info;

'73 Duster with /6 to 318 swap done with the regular bolt on goodies and a Crane cam installed. (Advertised @ 272/284 - .454/.480- 112 C-line.)
904 and Orange box ignition, MP distrib.

1st carb up was a small early AVS. Problem, will not idle. It can run on the main metering circuit, but not the idle. I could get it down to about 1,00 - 900 rpm's, but that's not the point. Swap it out for a

2nd carb, on the shelf I have a known 750 Carter AFB. A newer model purchased new by me about 5 years ago. I pop this baby on and it idles fine. However, no main circuit. Once I crack the throttle and the pump shot gets used up, it will stall.

I'm trying another AVS later. It is an OE part and it is the large ones offered.

Any ideas on wh the 2 carbs above are a problem. Now to add to the mix, yesterday when I tried to find out what was going on, I hooked up a vacuum gauge to the motor and found zero. I'm going to hook it up again to the manifol for a retry for a more accurate reading. The carb was the source of the intial reading. Timed stock to '79 specs for a base to start with since it is a '79 engine. It seemed like a place to start. and then go from there. Inital was 10+ ATDC/advanced.

 

[moper]

So...did you take either carb aprat and clean the stuff out of the bowls? Any carb coming off a shel for any amount of time will need at least a moderate disassembly and the passages blown out. My good carbs, I keep either in closed cabinets, or in plastic sealed bags. A dead spider in a metering block passage can ruin a nice afternoon, and you wont know until you pick the corpse out...lol. As a routine, I rebuild any used carb before it goes on anything. It's worth it every time.

 

[rumblefish360]

Hey Moper. The carbs were rebuilt and tested on the 400 B engine for working conditions. All was good. Removed and drained then covered with a red rag well. No webs inside anywhere.

Stand by for a copy and paste reply from else where slightly modified.

 

[rumblefish360]

Moper; I did just that with no luck. Below is a copy and paste reply to someone else on the topic. Read on;

This is what I was thinking since it is a stock long block 318 with the above mentioned. I was thinking the throttle bore may not be small enuff to make use of the vacuum signal. Which by the way is 15 inch on the auto meter gauge. (I was in a rush last night and hooked it to the carbs front ports (Both small ones) and found zip.

I attached it to the rear of the current big AVS and got a decent reading.

I started with a small AVS of a 340. Exact numbers can be given, just do not remember them now. The problem there was no idle circuit gas. I could get it down to a 1,000 rpm. But it was in the main metering. I used compresed air on all the holes in the carb. ...(Moper, And all the carbs tried. small AVS, big AVS, Carter AFB 750 cfm.)

Before I re-swap on the smaller carb and live with it....for now....I'm going to get into the carb again and richin it up since a low signal will be a pain to tune anything, the riching might help. I may have gone to far in setting up the carb only looking at the idle side of it. (Moper, not sure if this is the right direction?)

I mostly have good luck with the OE Carters. Never a problem with to big because they were never around to use. Allways the small ones were in house.

I'll be back tomorrow (I think) with another report and try. Whatchin the lil'guy now. HIs B-day presents are in the garage and I do not want him to see them if I start working on the car.

 

[rumblefish360]

OK, LOL on this with me and see if it doesn't sound like some of you out there with life keeping you busy. Something like I have, wife , collage, teenager, double shifts etc... Well, that's life and I love it but it does take away from the car time and when I get back to it all, I tend to forget where I'm at and writing it down does help, if I can remember where I wrote it.

On the carb, I just went back to the OE setting as per the Edelbrock catolog as it is the same jettings as the Carter when new. It runs. RICH! But runs. Now back to square 2. Re-jetting it so it doesn't stink up the hood and parking lots. Still pulls zero vacuum@ idle. I used the (Looking at the carb) lower left port for the vacuum gauge.

Boyyyyyyyy, I feel silly jetting it so lean it doesn't operate. But thats stop and go car work. Life don't do it. Just my time. LOL, well, anybody have a stab where I'll end up at between rods and jets?
(He he he) Thanks crew! Now if I could get the small AVS to act right.