We have a 1985 kawasaki stand up 550. We recently completely tore the carb down and cleaned it. The last week it would start up just fine and run pretty good but then it quit and it won't start. We have been adding fuel and taking it away and the plugs look the same and it doesn't really try to start unless we pour a little fuel into the carb itself. Then it will try to start, actually igniting, but quit and just keep cranking. Any tips?