Hello Stephan,
I’ve fitted a Beta 14 to A1. I could have fitted a Beta 12, but as it’s exactly the same size as the 14, I chose the latter. The 14 revs higher – hence the greater HP output. Run for the first time last Tuesday – seven hours, sweet as a nut. Hard to tell just yet, but appears to be just a tad over one litre per hour at 1800 revs through a 2:1 gearbox. This gave us 4.5 knots through the water. No doubt that higher revs more than possible – higher fuel consumption but 6 knots easily.
Cheers, Mike