I have a 1978 johnson 150h.p. motor. Recently bought it from a guy who never ran it on the water or on a boat. When I went to the guy's house, he started it and ran it for me and it idled good and seemed fine. When I got it home I removed the carbs and cleaned them, since I knew the motor had been sitting up for a long while. This is all that I did to it before putting it on my boat and trying it out. When I got to the lake, the boat started and idled well but when I throttled up, the boat would not get on plane. The cover was off and I could see that the throttle was wide-open on the motor itself. My father who was along for the ride, tried moving toward the front of the boat and it went ahead and got on plane. It ran fairly well but when we stopped we had the same problem. The next time we got it on plane it seemed to break loose and run like it was supposed to. I thought that maybe it was the fuel and just needed some running, but the problem continued. I then thought that maybe the filters on it were dirty or clogged. I removed the filters-pumps and cleaned them and now the motor will barely start up. Are these diaphram pumps that picky or do I just need to get new ones or a kit or something?
