With regards to a dyno for testing engines from ~ 40 hp to perhaps as
much as 150 hp, would anybody have some experience and/or advise which
make and type of dyno is advisable. Pros and cons of various systems?

Also, does someone have pre-owned equipment that is for sale?

Any help, hints or advise is much appreciated.

Regards
Rolf

Water pump dyno's are most popular but they require a lot of cold
water. Mazdatrix has an 800 gallon tank as I recall. When the water
gets hot you must let it cool off.

The cheapest is a prop load dyno.