power issue

[pointrunner]

hey guys i need your help, today i was running my 2003 90 hp yamaha at about 3/4 throttle at about 23mph when my power dropped, i opened up the throttle to full(usually hit mid 30s) and i was only going 7mph. We finally "*****ed" our way back at full throttle and 7mph when the motor shot up to normal and i trimed out. Took it to the dock and everything looked fine so i took it back out and everything ran fine and normal. My guess was water in the old fuel and it just had to work through or is there something bigger i should worry about?
-thanks, chris.

[boats.net]

Hard to say. Check compression, spark at spark plugs and check fuel system.

[pointrunner]

I was also thinking maybe the oil sensor is bad and it dropped into low rpms so it wouldnt over heat even though my tank was 3/4 full.