My guess is he is trying to use the same prop. He will need to drop down
about 4" of pitch.
Not sure why you would go w/ less power. Depending on the size of the
boat - this could be a real problem.
However, my guess is the prop is just too big.
He needs to prop for wide open rpms at about 4700 assuming it is a new Merc
engine.

--
Tony
my boats at http://t.thomas.home.mchsi.com

"john m." wrote in message
m...
My frend repowered a Four Wins boat, from a 180 motor to a 120 motor.
When he took the boat out he can't break plane with it. When he tries
to go full speed the bow kicks up and the stern drops down. He tried
different trims on the outdrive but still no luck. Even with the
outdrive all the way down so that the impeller points a couple of
degrees towards the bottom, the boats acts the same way. Is there not
enough power in the 120 to do the job?? I own a sailboat so I don't
know much about powerboats. Any help will be greatly appreciated.