Well... there was no choice in going with the traditional black as the flapper valves on it did not align with both ports so the teflon was used. And... that jogged my brain why the acetate membrane was used on the previous rebuild... because the black one in the rebuild kit didn't fit.

At any rate... problem is solved... motor runs great with no overheating. Can put hand on crankcase directly after stopping motor after ten minute run and it's not too hot to hang onto... sure couldn't do that yesterday.

The other interesting thing is that rpms are slightly less than was available yesterday where I could squeeze 8300 out of it but had dialed it back to 8100 and then on to 7900 where it still sagged and quit. Today it would reach only 8200 but it was happy running there and showed no sign of heating or sagging. Humidity today after rains is thirty points higher and temps are eighteen points cooler so that could be reason for 100 rpm difference. Evidently the Zinger 16x6 loads a little heavier than does an APC 16x6. I didn't have an APC off of a plane so didn't try one.

So, Karol... your advice to get shuck of the acetate membrane pump was good advice... thanks.