I have acquired a 20 hp. mercury outboard s/n<br />5610861 {1981-1982 ?}. It will only run on the top<br />cylinder. Thinking one of the three were bad, I switched coils, plugs and wires back and forth {keeping it in time} and every time I started it I could pull the bottom wire of and it would stay running, if I pulled the top one off it would quit. I took the power pack off and the white wire has been spliced {replaced}, the insulation is falling off and the wire is green and corroded. I do not know how the power pack works,<br />when it goes bad will it run one cylinder? with the switching around I did shouldnt it run one the top or bottom depending on the leads to the coils ? The p/n on the power pack is 339-622244<br />and is dated 9-18-79.<br /> My question is, could this be the power pack or a bad cylinder, I have not ran a compression check. I did not pay any thing for it and would like to know if It is worth sticking any money in it. The local dealer told me a power pack is $218.00 + laber and the engine is not worth it{they have not looked at it}.<br /> Any input or opinion would be appreciated.<br /> Thank You,<br /> J.J. 