Finally flying my IV. Today was warm at 90+ degrees.
I find that at climb power the engine is making 6300 rpm, same as static ground runs. I thought the RPM would go higher than static in flight. This lil engine is strong! EGT well below 1200. The water temp is coming up to 180 and will go higher if I don’t reduce power. When reducing power to ~5200 the EGT goes up to 1200 and water temp stabilizes at 175-180. Reducing power to ~4500 the EGT goes back down and water temp eases off a bit.

Copper radiator
100% antifreeze

I can experiment with water/antifreeze ratio.
I can lower radiator into the airstream a bit.
I can get a new aluminum radiator.

What else?

Would it help to repitch the prop to get more RPM?

Jon