Not an expert on Jon boats, but my brother's which is an 18' or 19'
with an older 25hp Merc does around 28mph if memory serves me. I
don't know how 'heavy' your heavy duty Jon is, but would not think you
will have a problem doing 15mph with any of the motors you listed.
Why not try deciding which one you'd like and put it on the dealer to
guarantee the performance you're looking for. Seems to me you're
not asking for a lot and a dealer should be able to figure if this is
enough and at least guarantee that much performence. Just a thought.

-Jim



New to Boating wrote:
Hand tiller outboards-Which would you choose?

Yamaha/Mercury 30 hp 747cc 3 cyl. $3500
Yamaha 25hp 498cc 2 cyl. hi-thrust model $3200

Suzuki/Johnson 25 hp or 30 hp 597cc 3 cyl. $3100 or $3500

Nissan 25hp or 30 hp 492cc $2800 or $3000

Honda 25 hp or 30 hp 552cc 2 cyl.$3500 or $3800

Going on a 18' Sea Ark MV1872 heavy duty (.125 aluminum) "super" jon
boat (80 hp max?)
fuel efficiency most important. Cruising at moderate speeds, around
15mph is the goal.
Is this underpowered @ 25-30 hp?
Thanks!