I finally got  all my fuel tables tuned to the point where it fluctuates less than 50 RPM just off idle.  This is without any active idle control.  I still need to work on the power end, but the coolant temps go from 180 to 200 in 60seconds at 4500 RPM.  That tuning work will take a while, even after I do some work to get better cooling.

But today's task was to take a look at timing. The methodology was to set the throttle just off idle, then leave it alone.  Let the engine smooth out, then, with the recorder rolling, slowly move the timing up and down to see the effect.

Going up to 28*, the RPM hung around 1905.  Dropping back to 23.3, brought me down to about 1880.  19.6 got me 1860, and 15.6 produced 1830.  Now, these aren't exact numbers...more of an eyeball average, but 15 degrees of advance only made about 75RPM difference.

The trade-off is that more advance means more stress on the system, and more heat in the coolant. Would it make sense to accept the power loss, and dump the heat out the exhaust, or should I keep searching above 28 for more power?  Other than a backfire and a broken apex seal, what signs would the engine give you that it has all the advance that it really wants?