Microlighters

I have found this on a german website Sorry for the low quality of the picture

It means:
Power told by the manufacturer
Power at the propeller
Net weight (I suppose with all accessories including exhaust line and engine mount)
Cooling system (Wasser = Water. Luft = Air)
Weight / Power Ratio

PS is HP.

I am surprised by the Jabi figures. You would think the engines being direct drive, i.e. no gearbox, would produce the same power as on the crank.

Agree with you. Crank and prop flange the same thing

They reduced the prop RPM to give the bad figures. Don't know why they chose 2700rpm, as that is even below the recommended cruise RPM, never mind max continuous RPM!

Continuous power (at the prop) rating for modern Jabiru engines is 83hp and 115hp (possibly 107hp - sources differ) respectively.

That's the reason why it would be interesting to organise a dyno test.

The Jabiru curve shows that at 2700 rpm the power is 57 kW or 76,4 hp.
This above table shows that at 2700 rpm the power is 63 hp. (17,5% less that it would be).
An engine manufacturer (don't ask me which one !) told me it is 65 hp (but he is not very talkative I don't know at which rpm he took the measurement).
These tests were certainly done with propellers on. That's why it is only 2700 rpm for the 2200 Jab.

Who owns a good dynamometer ?

A dyno won't help at all. All of the published figures are dyno figures, and they will be pretty accurate.

What is really needed is some sort of comparative propeller efficiency test. But that is extremely difficult, as the fuselage shape (up to one prop diameter behind the prop) has a huge effect on the prop efficiency. So for some airframes, you get very good efficiency, even with a short, high revving prop, while for others youe NEED a long, low revving prop.

There is no magic 'this engine is better' measurement. About the closest you can come is to say 'for this particular airframe, this engine gives the best performance'.