so the starter is fixed, the plugs replaced. Now all of a sudden the yahmaha 150 2 stroke will not go over 2500 rpms when in gear. In neutral it revs up fine. then when we are looking to get moving...no go.
Trouble shooting tips?

could be the diaphram fuel pumps. they used to go on my yamaha250's about every year and a 1/2
causes a Whaaah-Whahhh-Whahh RPM fluctuation. can't get enough fuel.
search Iboats.com forums in the yamaha/susuki section

Does sound like not getting fuel.....
have you recently changed you fuel filters?

Or maybe a spun prop ???

New plugs, could you have crossed a wire?