My brother has just bought a Glastron GT150 with a Johnson 85hp V4 (2
stroke) outboard (circa 1975-1978) and whilst he is very pleased with
the combination, the fuel consumption seems a little startling.

Anyone have any idea what the approximate fuel consumption ought to be
on this engine at full throttle? I guess it would be better at more
moderate throttle settings, but where's the fun in that!?

Are the modern equivalents of this engine much better in terms of fuel
consumption?

Cheers

Guy