20 hp johnson missfire

[billgri]

i have a 1987 20hp johnson that seems like has a lean missfire but i cannot find anything causing it to be lean,question do the coils fire at the same time ?its popping through exhaust but when i pull plug wire off bottom cylinder it smooths out and put bottom plug wire back on and pull off top cyl wire it dies i tried switching the coils and had no change ,and then i tried switching the voltage supply wire to coils and it wont run,iam thinking i have a bad power pack any ideas of what else to check or any ohms checks i can do to verify?any help i would appreciate it thanks

[boats.net]

If it is a lean pop then that is usually associated with carburetion. Verify spark with a spark tester, if you are getting good spark all the time then not likely ignition (unless your timing is off).

[billgri]

why would it smooth out on top cylinder if its lean it would be lean on both cylinders correct? and its a manual start so pretty hard to determine if spark is consistent all times,is the orange and blue wire and orange wire that supply voltage to coils the same (voltage and time) do they fire at same time can they be swaped and work ok?are the coils supposed to fire at same time ?