The issue of "low power" was actually a problem with high temperatures (even at max RPM the temp should remain below 740 C).
The new combustor has resolved that (Bill's engine does have the new combustor).
The Wasp has never had a problem with "high fuel consumption".
In fact it has always been slightly more efficient than most (~240 ml/min @ 18 lbs thrust).

At 141 krpm, Bill should be seeing about 16.5 pounds thrust.
At 145 krpm, you will get roughly 18 pounds and at 150 krpm you should get about 20 pounds thrust.
I recommend limiting the top end to 145,000 rpm.
Also, I highly recommend using top quality, high temperature, synthetic turbine oil (BP 2197, BP 2380, Aeroshell 560, etc.).


ROB