[C320-list] Outboard Motor Selection?

[Jeffrey Hare]

Hi all,
 
   I've got a 10' wooden floor dinghy with an inflatable keel.   A 4hp
4-stroke motor will just barely get it on plane with myself and my daughter
on board with total weight of under 200lbs.
It won't climb onto plane with my wife and son on board also, even with
weight shifting around.  (didn't expect it to really).
 
So, with under 400lbs total weight, does anyone on this list think there's a
chance of a 6hp 4-stroke outboard being able to plane?   Doesn't have to be
fast, just fast enough to get on plane with the weight properly distributed
so that the ride is relatively dry.
 
Stepping up to an 8 or 9.9hp merc adds another 40lbs of weight and ~$400 to
the tab.   I was hoping to avoid having to hoist a 100lbs motor anywhere.
The 6hp is under 60lbs.    I'm not really interested in a 2-stroke.   I
already live in 2-stroke hell around the house, plus I already have a
tempermental  7.5hp merc 2-stroke that's always on a coffee break when I
need it run.
 
-Jeff