I used to have one of those, but it was the 20 HP (same engine family). If memory serves me correctly, the 20, 25 and 30 HP are the same engine and all you need are some jets and timing changes to get more power out of her. I think there's a throttle limiter cap you'll have to pop off too. Considering it's age, it's in need of a full up rebuild, if it hasn't had one yet. She's seen some service, such as the lower coil, looks newer then the upper and someone has foolishly installed a glass, reusable in line filter, which should be tossed in the trash, before it breaks and causes the obvious problem. If inspected (and tested) by a qualified outboard mechanic, you'll get a much better idea of what shape it's in. Pictures don't tell us much about how it runs, shifts, etc. Most would regard this engine as an antique, so pick your poison wisely.