Originally Posted by Alan
For max endurance and min hassle go for a 4 stroke and get it plumbed into the main tank. (assuming you have an oil injected or 4 stroke main engine)
... and what happens next if it happens that the main engine seases due to water (say hypothetically) in the main tank. Your aux engine goes in the bin too and start using the flippers or get down and push the boat?
For the Scorpion I think a Tohatsu 5bhp 2stroke (I am not into the 4 strokes yet) with its own little tank on it will be OK...ish. I do do not know if the bigger Tohatsus have own tank but the bigger aux engine you get the better for a boat of that size and weight will be.
Nice choice of a good seaworthy hull and hope that you enjoy her.