Hello to everyone! I have a 1986 75 hp Mercury that's giving me fits! Engine runs great for a while (idle and wot)then it won't idle at low speed. I have rebuilt the carbs,fuel pump,replaced spark plugs and fuel line from the tank. I can pump primer bulb until it tightens and then pump it harder and I hear fuel hiss at the carbs and the bulb softens some and the engine will run great. It may run like this all day or 15 minutes. I've checked compression and have 90 psi on all four cylinders with engine cold.I've added Seafoam to fuel with little or no help.Engine will idle up with choke pushed for just a second at low speed and sometimes it will take care of it but most times no help. I can't rev the motor out of gear because the throttle only button doesn't work on my controls. I know it's something simple,but danged if I can figure it out. Any help will be greatly appreciated. Thanks!
