Alright heres my problem, bought a 1978 Baja Ski Boat with a 1978 Mercury 115 Thunderbolt Ignition Motor. It was my dads, practically grew up on the boat. Anyways always had to start it by pumping the bulb, cranking while holding the button for the solenoid choke, pumping bulb again and then cranking with throttle lever up. Usually fired up even after sitting up for a year. Well now its really hard to start and will not idle. I do the above mentioned starting procedure but have to pump the bulb multiple times, and hope my battery is really good. It will slowly spit and sputter until it cranks, revs up with the throttle lever up and then shut off. Then I have to pump the bubble again and crank it again, revs up and shuts back off with throttle lever all the way up. The weird part is I can get it to rev up and kick it in gear and floor it. It will run and stay running until it gets close to idle speed and shuts off. I should mention that I have a new gas tank and had unhooked the throttle and gear cables to remove the motor to get the transom rebuilt. The motor ran before it was taken off for the rebuild. Also cleaned but not rebuilt carbs, and had to put two new fuel lines on.