I have a 1994 Mariner 75hp outboard. Runs great for a while (maybe a half hour; maybe an hour), then starts hesitating. I press in the choke, and it will speed up most of the time, but it will slow down again. Usually happens above 2500-3000 rpms, but will stall at idle also when this happens. Had to limp home today (surge-hesitate, surge-hesitate) by pressing the choke off and on. Fuel is visible in the clear fuel filter between the tank and the bulb. I?ve rebuilt the fuel pump, replaced the fuel hose including the bulb, removed and cleaned the fuel tank and pickup tube, replaced the hoses in and out of the fuel pump, replaced the spark plugs, run Sea Foam in the gas. This started about mid-summer. Help!! Ideas anyone? Thanks.