I have a 46FX that is several years old with probably a 1000+ tanks of fuel thru the carb. Over the past year, I noticed that the engine will only run well if the needle valve is tuned out about 1/3 turn from stop. The last couple of times it was turned all the way in to run right. I replaced the needle valve and this made no difference. Fuel lines look good and engine seems fine. It has been a strong running engine, but this problem has me stumped. Running a pitts muffler.