50 hp 3cyl 2006 yamaha

brought boat to shop.told i had water in fuel tank.they drained tank and supposedly flushed carberator/fuel lines/change water seperator. first time putting boat in water,wont start.i spray starting fluid in intake and it starts and runs til fluid burns off. checked fuel filter, and all lines after that.fuel flowing thru lines,fuel pump when i squeeze primer bulb. how can i test fuel pump to find if its pumping fuel to carb ? if it is getting to carb , what would be my next step to flushing/cleaning carb ? any help would be appreciated as i don't want to bring back to shop and spend $$