I had an OS32H in a Caliber 30. No matter how I tuned it I couldnt hold my finger on the backplate.
As I was concerned about this and wanted a little more power I upgraded to a OS37SZ. I still cannot hold my finger on the backplate no matter how I tune it.

I do live in the tropics with average OAT around 30-35C so I assumed that was why.
I run it as rich as I can, any richer and it bogs slightly. Still a hot backplate. So im not convinced about the backplate method.

OleC

Your running watercooled Heli in Norway. Must have had a hot summer there. It would run very cool in winter then.
How do you water cool your engine. Is there a marine cylinder head or similar you use.

Cheers