1985 GSL
Dual Weber DCD Carbs
Holley Blue pump and regulator set @ 4.5 PSI
new cap, new rotor new fuel filter, new plugs, new plug wires
No rats nest, no vacuum advance(stock timing)

I got them sync'ed together as good as I can. Idles perfect and mid to full throttle is fine. Any light throttle it hesitates and usually stalls unless I ease into it EXTREMELY slow. Doesn't matter if it's warmed up or not. It doesn't matter what RPM. It's light throttle under load. It free revs fine. The only way to get it to work right is to tug on the choke a bit and it takes off. I'm stumped. I've cleaned, adjusted, re-cleaned, re-adjusted. I did try bumping my timing up to about 5* didn't change anything. The carbs are stock port jetted as far as I know. It's the Rotary Engineering setup. Can't find any vacuum leaks......I'm stumped. Any suggestions would be great.

 

Having to use the choke indicates a lean spot or poor venturi velocity. Time for wideband tuning. Shoot for around 13.5 to near 14 AFRs. I used Holley air corrector jets. Don't recall the exact size, but then I'm running a 1.2 SP-1/2 BP 12A. RE's original jetting was set up for their large SP engine, but I imagine they jetted for individual orders.

One thing you need to watch is how soon the secondaries open up. There is a screw adjustment on each carb for that. If they're opening too soon or you're pushing the accelerator pedal to deep, that may be part of your flat spot.

 

I thought of that but, I can't see when the secondaries are opening and drive at the same time.
Where is the adjustment screw? All I can see is on the out side of the carb the primary plates have a little cam-lever-lookin-thing that rub on an arm attached to the secondary plate.

 

I had to go look at my spare set of carbs to check where the adjusting screw was. I then realized I gave bad advice. The box like structure under the throttle lever arm contains the cam and gears for the secondaries. On the outboard side, passenger, side of that box is the adjusting screw. You want to adjust that screw so that when the primary throttle plate is fully open, vertical, so is the secondary. Sorry for the error.

 

Everything seems to be working fine mechanically. If the carb was jetted for a large port wouldn't it be running rich instead of lean?

I know the Rotary Engineering company is no more but, are there any of there techs still around?

 

I'm thinking you have the same problem alot of us face. The symptom is the same! Go to the GSL SE problem resloved thread here.
Basically says you have a clogged screen and or return line in the tank. I found out that was my problem too. My car idles fine and really light throttle, but step on it even a bit and bog. Sound familiar???

 

Pretty much. BUT...the screens are clean, I have no return line (Holley pump/regulator) and it didn't happen when the air temp around here got above 50*.
Still tinkering not really getting anywhere. lol

 

Don't know much about the Webbers, especially the DCD twin set-up,but sounds alot like you have an issue with the accelerator pump. If you don't get a shot of gas when you open the throttle butterflys, you will stumble and potentially stall.

Hope this helps.

RXDad

 

I'm almost convinced it's the cold weather. It got up to 50* and no more stutter until it dropped back down to freezing.
Also, I realized that my trailing and leading plugs were firing backwards. So my leading plugs were, in essence, 20* retarded. Kinda feel dumb not realizing this but yeah I got a little more oomph now!