Need help. I HAVE A 2001 HONDA 90 HORSE 4-STROKE , EVERYTIME I START IT UP IT WON'T IDLE. IT ONLY HAS ABOUT 50 HOURS ON IT, DUE TO SICKNESS. START IT UP AND TURN CHOKE ON IT WILL RUN. TURN IT DOWN IT WILL STOP. HAVE CHANGED GAS, NEW FUEL FILTER,CHANGED PLUGS STILL NO GOOD.CHECKED EVERYTHING EVEN DRAINED CARBURORATER.STILL NO GOOD.ADDED CARB CLEANER AND GAS ADDITIVE.CAN'T GET INTO CARBS. IS THERE ANY THING ELSE IT COULD BE? IF NOT DOES ANYONE KNOW HOW TO TAKE THE PLASTIC COVER OFF? BOLTS HARD TO GET TO.THANKS, SHERWIN