Is it possible to have the detailed specifications on the Beta 50 ? On the UK site for example we can see the max HP but not the prop curve HP. But the fuel is on a prop curve but then we do not know if it is exp 2.5, 2.7 or 3.0.
Also what about the emergency duty of such engines; suppose we are stuck in a storm and want to run the engine continuously for 20 hours at the maximum power possible, what value of rpm in percentage of the maximum would be authorized ?
We use 'propeller law' for the fuel curve as it give us an average figure, as essentially, whatever load is created on the engine by a propeller, if it is load matched to the engine to give maximum performance without overloading the engine and causing smoke, using the transmission ratios available the load essentially ends up being the same. That is correctly load matched based upon an average boat so that the engine will reach maximum RPM's.
Finally, to you final question. Kubota's published SAE Gross Intermittant rating is 49HP at 2,800 RPM at the flywheel with a SAE Net Continuous Rating of 40HP at 2,800 RPM.
Added Note: It is OK to run this engine continuously at 2,800 RPM's for 24 hrs.