I have twin 96 model 115 proV yamahas on my 24' grady. I bought the rig second hand and after about four trips had problems running at idle. Took it in and had the carbs boiled out and rebuilt on both egines. Gummed up fuel and accumulations on the low speed jets were the culprits. Since then I have run about 900+ gallons of fuel and have kept the canister filter changed and added stabil each fueling. My port engine on the last two trips is hard starting. To cold start it requires no choking, and no throttle. I can smell it flooding out. When it does start, I have to keep the rpm's up or it will stall. It runs great at cruising speed. When I back off to circle a spot it will stall unless I keep the rpms around 2000. what would cause it to flood out or run so rich?