Hello,
I have an 2005 f225 four stroke yamaha. The boat only has about 300 hours on it. Since I have owned the boat (3 years) the motor has run perfect. I had let the motor sit for about 2-3 months. Then it had trouble starting.

After flushing the fuel system and changing the spark plugs (because it was time, old plugs looked fine though) The motor starts and idles rough. In neutral the the motor will rev through its rpms fine but when in gear the motor will not go above 2200 rpms.

After inspecting the new spark plugs, after being ran for about 30 minutes, plugs are dry and very black with the exception of 2 of them are white and dry. ( suspecting two cylinders are running lean)

I am suspecting clogged fuel injectors or still a blockage in the fuel system. If this is the case will cleaner that is added to the gas tank be the way to go or would I be better off cleaning the system out another way.

There is a brand new fuel/water separator filter on and no water can be seen in the bottom. Same with the fuel filter on the engine.

If anyone suspects anything else please let me know
Thanks in advance guys!
Chris