Published 2013 Updated 2018
How I installed Weber's on my stroker
by Gary Yasaki
I installed a pair of 40mm Weber DCOEs six weeks ago and thought I'd share my fun experiences. First off, they were installed on a 1600 stroker with 9.2 compression ratio, M-13 mild street cam from American Cams and a ceramic coated heater with heat wrap. Mildly ported head and intake manifold. The Weber kit (carbs, linkage and manifold) were purchased on Ebay last year for $850 and originated from Pierce Manifold, a large Weber dealer in Gilroy, CA. The manifold had to be worked on with a die grinder because there wasn't enough clearance for the fat washers and nuts to mount it. There's also two big bumps inside two of the intake tunnels from the casting design and I flattened them down a good bit. There were no instructions and it came with an assortment of 20 extra jets which meant nothing to me at the time. I set them up on the 1600 last year before the stroker and had a nightmare of a time trying to find out why one carb dripped fuel all of the time (directly onto the hot exhaust header below)! On and off numerous times and it turns out it was a faulty casting and after Pierce bench tested what I found, they promptly called me and sent me off a new one. By the way, Pierce has a large Ebay presence and the prices are less than their web site and usually have a much lower shipping rate.
I installed the Webers on the stroker when it was complete and first off, it dieseled badly on shut down and wreaked of gas (again). Really badly. Turns out the fuel was boiling in the float bowls and coming out of the intake velocity stacks. They were getting so hot you could hear it percolating on shut down. I installed four 1/4 inch phenolic spacers I got off Ebay, had to get longer studs and also made up an .025 aluminum heat shield. I also added some Thermo Tec adhesive backed insulating sheets to both sides and now they're just warm to the touch and have just a faint gas odor. The dieseling on shut down seems to be strongly related to the idle mixture screw setting which is now at 1 1/4 turns out for the most part. Webers need lots of timing so the Dizzy is set at 36 degrees total. They also need fuel pressure set no higher than 3 psi so fortunately my electric pump was right there. Carbs are synced using an SK carb flow meter. Very easy to use and less than $30
Here are some sites that really helped me get a sense of what to do as finding someone with Weber tuning experience is pretty difficult. At least someone willing to help out a looser without a Ferrari or Alfa Romeo.
https://www.classiczcars.com/forums/topic/50379-sidedraft-central/
http://www.timsroadster.com/html/tuning_webers.html
Current jets are MJet 135, air jet 160, emulsion tube F15, idle jet 45F9 You forget about a choke and just 4-5 quick pumps of gas and they start right up. The accelerator pump shoots gas into the intake. Works great. Update to the jetting 9/5/21 F9 emulsion tube, 140 Main Jet, 180 Air jet and 60 F9 idle jet.
You'll get an understanding of how to do the base set up and also what does what by reading those sites. Just as vital is to use a wide-band air/fuel meter which I was lucky enough to borrow. You'll be lost without one. Turns out I used all of the jets in the bag so it may have been shipped set up for a 1600 and the extra jets are for a 2000. It's very easy to swap jets in a Weber so that's a big plus. They are complicated at first until you get a basic understanding and keep track of what you're changing. Sounds and runs great now and I just love looking at them.
Here are a few pics of my install.
Gary