I have a 1991 Johnson 60hp motor. It belonged to an old man who let it set up the last few years of his life. I had the carbs cleaned, new filter, and new plugs. I still have a problem starting the motor. I will throttle up in neutral and try to crank it. After a few tries, it will start for a second then die. It will do this about 4 or 5 times, then eventually start. Does anyone have any suggestions?