Any ideas what the proper advance curve is? I've been having problems lately with backfiring and dieseling, so bought a timing light (mine back home doesn't do me much good here!), and checked the timing, thinking it might have drifted since last time I set it. It tested perfect 5 degrees at 650rpm, but for the heck of it, played with my idle speed knob...

450rpm: 0 BTDC
650rpm: 5 BTDC
800rpm: 10 BTDC
1000rpm: 15 BTDC
1200rpm: 20 BTDC
1500rpm: 25ish BTDC (off the end of the scale)
Anything higher: 27ish BTDC

That's a pretty steep advance curve... Is that normal for these, or are my springs bad? It's a civvy dist, with the vacuum advance disconnected and capped. I'd normally expect to hit 25 degrees around 3K-4K...

--Randy