As far as a 5 hp o/b goes, this is what I've seen some people do to have a 4 stroke 5.5 hp o/b for around $200.
Find a blown motor, usually on C/L or at a repair shop.
You don't need the engine, just the rest of it.
Go to Harbor Freight and get their vertical shaft 5.5 hp lawn mower engine and mate it to the o/b lower end.
Or use a Briggs off a mower if you please.
Sure its air cooled and noisy but it's super cheap.
