Danny Wheeler
New member
I have a 1998 mercury bigfoot 50elpt4s. serial 0G697866. This is a 4 stroke outboard with 4 carbs. I have been told that the main block is a Yamaha block with mercury parts on it. This thing has been a crap shoot ever since I got it. right now I can get it to run good. But it seems if I let it sit for more than a week I have to pull all the carbs off and run them through my ultrasonic cleaner. When I do this, I take the carbs completly apart. I take all the jets out and clean them. Then When I reinstall them I have to balance the carbs all over again. Once cleaned and reinstalled the boat will run great. I am trying to find a way that I do not have to clean the carbs all the time to get the outboard to run. It is a pain to clean 4 carbs and then rebalance them. I have replaced the entire fuel system. New tank, to primer bulb, new hoses, new filter, new fuel pump, and all new connections. I have tried sta-bil, merc clean, and Lucas marine fuel treatment. I have even ran the carbs out of gas, and emptied the fuel tank so the next time I run it if it will be a month I will use fresh clean fuel. I have even tried ethanol free gas. I must be missing something. When I pull the carbs off they do not even look dirty but I am guessing the small jet may be getting something in it that I do not see. any help would be great.