welcome aboard
free boats are the most expensive boats in the world. Think about it, if there was any value in the boat, you wouldnt have gotten it for free. and one of the worst free boats you can get is one with the 3.7 motor.
most likely your accelerator circuit is needing help. either the accelerator pump is shot, or the circuit is plugged
with any new to you boat, make sure to do all the maintenance:
gimble bearing
raw water pump
alignment
bellows
u-joint check
gear lube replace
engine lube replace
fuel filter replace
cap/rotor/wires/plugs
in addition to that, with the 3.7
pressure test the exhaust manifold
pressure test the engine
inspect the cam seal
compression test
