Thats plenty of time for fuel to start to "varnish", it is sometimes easier to tell by the smell. Remember the filter does nothing to filter varnish. A good practice is to use STARTRON or other fuel stabilizer as directed. Time is one of fuels enemy. It will be more of an issue as warmer weather rolls around but generally speaking people use there boats more when the weather is nice. My suggestion is burn that fuel up quickly or drain most of the tank, refill and add fuel additive with stabilizer. I have the same set up on my 125 MERC and run my boat year round without a problem. Drain that bowl before every trip and you wont have the ethonal issues many experience.