Trying to track down a miss/uneven run

[GoWestYoungMan]

Newly rebuilt 1776 with dual Weber 44's. Starts good, seems to run good, tons of torque at wide open throttle.

But when she idles there seems to be a miss or an uneven run. So I pulled the plug wires off the distributor one at a time to see which cylinder it might be.

When I pull either cyl 3 or 4, she stumbles and will stall out, but when I pull cyl 1 or 2 off the dist, it barely makes a difference. In fact I pulled both 1 and 2 at the same time and she just kept ticking right along. What the heck? How can it run that evenly on two cylinders?

I tested the plug wires with an ohmmeter, they seem to be ok. Pulled the plugs and they seem to be ok too.

I'm trying not to imagine it's low compression on cyl 1/2 side (don't have a compression meter here at the moment) cause that would suck, but what other possibilities are there?

[jsturtlebuggy]

Have you balanced the carbs?
_________________
Joseph
Fair Oaks/Orangevale, CA
Elrod Motorsports
Motion Tire Motorsports
Having fun with Dune Buggies since 1970
Into Volkswagens since 1960

[GoWestYoungMan]

Can't say I know how. I'm new at this but I'll look it up.

[jsturtlebuggy]

Yes you need to make sure that both side carbs are pulling the same amount of air flow through them.
There are a couple of type of tools for doing this and with dual carbs it is a tool that you need.

What you describe with the way it running at a idle is that the throttle plates on the one side are close to were it not able to pull any fuel through the idle circuit.
The book that CB Performance produced and many sell about tuning of dual Webers has a lot of good information.
_________________
Joseph
Fair Oaks/Orangevale, CA
Elrod Motorsports
Motion Tire Motorsports
Having fun with Dune Buggies since 1970
Into Volkswagens since 1960

[GoWestYoungMan]

Thanks jsturtlebuggy, that was indeed the issue. The carbs were definitely out of sync. Got it pretty close by following the procedure here: http://www.redlineweber.com/html/Tech/idf_adjustment_controls.htm

The main thing I wasn't doing was disconnecting both sides from the throttle linkage and setting the idle mixture settings individually for each carb. Once that was done, hooking them back up together made things much more even and the cylinders are all pulling now, not just one side.

I'll spend the $50 to get a snail gauge eventually but for now, I'm pretty happy that there's not some major issue with the rebuild. Thanks again for your insight, that really helped!