Last night while fixing my boat (1978 sportcraft with 1978 mercury 800 80hp with mercocontrol) i started it up and my girlfriend's dad noticed it sounded a bit weird. He started taking the wires off while idling and top plug(cylinder) made no difference. The bottom 3 would shut the engine off. We did a compression test and got 75 for each plug. There was spark to each plug. I went and bought new plugs and it didn't make much of a difference. Did sound a bit better since the guy had 3 champions and 1 ngk in it. It idles, it runs high rpm when using the idle lever. If that helps. Could it be a wire? Even though they're all getting spark? What about the power pack? If that was bad though wouldn't I have 2 cylinders not firing? I don't know. This is my first boat and want it to run so bad. At this point I'm getting frustrated. I've finally fixed all the small kinks and now this. Any help is greatly appreciated. Thank you!
