I just did a carb balance on my Sky Arrow as part of this year's annual condition inspection, and posted my learning experience back to the VANS forum. I thought it might be of interest here as well...
As a follow up, I just did my carb balance as part of my Sky Arrow's annual condition inspection. It's not on my checklist, and I did not get around to it last year and figured it was about time, though my engine did feel about as smooth as always.
Everything is a little tougher with a high-mounted engine and a pusher prop. This time, I hooked up long extension hoses using some oxygen hose I had and ran it up to the cockpit:
It appears I was overdue:
Anyway, the Law Of Primacy is still strong with this one - in spite of the previous discussion in this thread, needing more throttle on the left side led me to adjust the barrel adjuster to take slack out, which, of course, is backwards - you need to screw the adjuster in to allow the springs to pull the throttle lever towards a more open position. All opposite to my BING experiences on BMW's.
I was wondering why my adjustments - in both directions - seemed to be having little or no effect. I'd loosen the lock nut, screw the adjuster in or out and tighten the locknut again. I was missing the fact that the adjuster on these carbs are not threaded into the support arm - I thought they were. After that "Aha!" moment, it only took two tries, adjusting the nut on the barrel side, to arrive at this:
It appears about 1/2" off in the photo, but the two vacuums were tracking pretty perfectly throughout the rpm range. I think there may be a touch of parallax error in the photo as well.
Thanks for the input and corrections - I think it finally got through to me!