115 4 strokes - no top end power

[Playinhookey]

I own a boat with twin 115 Yamaha 4 strokes purchased new in 2004. The motors have performed flawlessly until this year. They will start and idle fine but when I want to give them throttle they start to miss and sputter and act fuel starved. The one motor will usually stall out but will always restart. I've been using Startron and Stabil in the fuel. I change my 10 Micron fuel-water filters every year. I was told by one mechanic it may be the filter in the vapor separator tank (I've never changed these). Another said it sounds like clogged injectors.
Any suggestions would be appreciated.

[99yam40]

check fuel pressures that will tell you something about filters.
Kind of strange both have the problem so it could be your fuel is contaminated